Released a year after the first Descent, Descent 2 plays and looks very similar to Descent 1 to the point of seeming like just another expansion pack like Doom 2 was to Doom, but there's been a lot of changes that makes Descent 2 stand out. For starters, the size of the weapon arsenal has been effectively doubled. There's a second weapon bound to each key, and there's even a new mine type. All the enemies in Descent 2 are completely new, some of which behave similarly to their D1 counterparts, but others are entirely different and have their own unique behaviors. You are given several new gadgets, such as an afterburner to give you a short burst of forward speed, headlights to illuminate dark caverns, markers which you can place in levels in order to highlight areas in the auto-map, ammo rack pick-ups double your maximum ammo capacity, full map pick-ups show you the entire map, new Super Laser boosts boost your standard laser from any level to level 5, and a shield/energy converter which converts surplus energy into shields. Level geometry is much more complex and feels less blatantly cubic, and levels are now more interactive. Lights can be shot out to darken a room, and there's switches which can be shot to trigger other objects in the level, such as opening doors or disabling the new forcefields.
Another big addition is the Guide-Bot. This guy is the only "friendly" bot in the game who you can command to lead you towards the next key, or to lead you towards items and the level exit. Probably in response to untermensch complaining about the levels in D1 being too complex, not you can just follow the robot around to get around. The untermensch did appreciate this feature, even though you can entirely do without the Guide-Bot's "help". You're not expected to use the Guide-Bot, in each level the Guide-Bot will be locked behind a grate which you need to destroy to have it lead you around, which you are never forced to do. The pathfinding on the Guide-Bot is very much on point and helpful, in that regard. You might be wondering why you wouldn't want to have a helper always showing you the correct path in the level other than posing a challenge for yourself, and the reason for that is that the Guide-Bot is an annoying piece of shit.
The Guide-Bot will shoot flares to get your attention and show you the way, however sometimes it might hit your ship. Which only deals 1 HP damage, but it gets bloody annoying when it happens multiple times. It also might end up accidentally shooting a flare into one of the mines you placed and ruin the trap you were setting. It might end up opening doors with enemies behind them which you don't actually want to open yet. If you are controlling Guided Missiles, it might end up shooting you to get your attention which in turn automatically boots you out of the Guided Missile view. It gets too damn noisy when it gets stuck. Thankfully you can send orders to the Guide-Bot and tell it to be quiet and fuck off, though it keeps following you around if you manage to accidentally bump into it again. There's also a peculiar bug in the sourceport where it crashes if you blow up certain enemies with a missile if you told the Guide-Bot to go away. I don't mind all this too much since I never needed the Guide-Bot's help, and casuals who do probably won't care too much about it being a fucking annoyance. Unfortunately, some levels feature a secret area inside the Guide-Bot's jail cell, which means you have to break the Guide-Bot free to get to the secret and tolerate it's intolerable presence. I've come to regard this type of secret as a Descent level design sin.
The AI has seen an important change: enemies can now lead their shots as well. Meaning you can't robotically constantly dodge all shots by moving in a rectangle, but frequently have to change up the direction you're moving in because the enemy can predict where you're going and compensate their shots accordingly, making dogfights against even the weaker enemies more involving. The AI is still devious and unpredictable as ever with each enemy having its own distinct behavior, some perform hit and run attacks, some hang out in the back, and some aggressively rush you.
Matcens in Descent 2 can no longer be depleted. In D1 you could trigger a matcen three times to deplete it of spawning enemies again, but in D2 a matcen can be triggered infinitely. I would say this is a good change, you no longer have to pre-emptively trigger matcens and safely spawnkill the enemies it spawns three times so you could have a safer journey later on, which saves a lot of time (though if you do end up triggering a matcen, standing in front of the matcen and spawnkilling everything that comes out is usually still the way to go). On the other hand, this does make matcens more susceptible to milking, since some matcens can spawn enemies which drop ammo and shields which you can milk for as long as possible, depending on the level (that's why you usually place two matcens at once to make controlling them both at once hard to do). To me the ideal solution would be to let the player destroy matcens (like in Overload) and skip the boring spawnkilling phase entirely.
Descent 2's approach to difficulty thankfully differs from Descent 1 and is much more suitable to its own style of level design in gameplay. Descent 1 would often ambush you with highly powerful enemies which you couldn't dodge without foresight and which would instantly kill you. Descent 2 on the other hand prefers to slowly whittle you down. For starters, Descent 2 does not have the fucking Red Hulk or Class 1 Driller, and even the D2 equivalents of those have been nerfed into the ground. Descent 2 presents a lot of nuisance enemies at once which might sting you if you face one alone but overwhelm you when they come in numbers, and some of the more tougher enemies are usually placed in positions where they can be sniped or reliably fought without tanking too much damage. Overall Descent 2 is harder than D1, though the increased difficulty doesn't result from bullshit unlike in D1.
Levels in Descent 2 are somewhat more spacious than they were in Descent 1, giving you more maneuverability over enemies, but since they can lead their shots now you're going to need that space. However, the levels in Descent 2 can't be generalized as easy, they are much more varied on the whole, so levels often have a mix of tight tunnel sections and larger shooting galleries. But overall the levels in Descent 2 are much more complex from a combat and exploration standpoint. Especially concerning the latter, some levels made me salivate with the sheer amount and usage of secret areas at play, and the non-linearity of some levels. Some levels allow you to straight-up skip some color gates and keys for the final red one. Secrets in Descent 2 are much more tricky to find and are more numerous, on top of that secrets in D2 are less of the hidden wall-type like they were in D1, and that's because of the presence of switches.
Switches when triggered can open hidden walls, permanently unlock doors, and also temporarily open some doors. Not just switches, but just decorative screens when destroyed can also trigger secrets. However, the switches which temporarily open doors are rather annoying, because if you do shoot said switch and don't know what the switch opened, the door in question will close permanently and you will have to reload the level if you want to access the area behind that door again. Which is rather annoying to deal with. A better idea would have been to not make the switch destructible and infinitely triggerable so you can always try again to open the door. Though the best solution would be to keep the thing permanently open and/or unlocked. There are two sprites for switches, but none of them are used consistently with what they end up triggering, so red or green switches don't always open or unlock respectively. Meaning you're most likely going to be saving before each switch to figure out what it does, which is ideally unnecessary. It doesn't help that you can forcefully keep any door open by placing a marker at the door entrance (even though markers appear to be a hologram only visible to you) to skirt around the temporary opening times.
The singleplayer campaign is also structured differently from D1. Whereas D1 was about hopping from all the planets and moons in the solar system and the levels only sometimes having a thematic semblance to the planet they're taking place on, D2 is divided into episodes of four levels. Each episode has you travel to another system and introduces its own new set of enemies and texture set, with the fourth and final level of each episode having you fight a boss enemy at the end instead of a reactor like usual. While this does make the progression feel more coherent and regularly introduces new enemies even up to the very end, the levels themselves might end up feeling visually repetitive whereas D1 was full of surprises for what the next level would look like, though your opinion might vary with each texture set.
Secret levels are also done wholly differently in D2 than they were in D1. Whereas the secret levels in D1 played just like a regular level, D2 secret levels are more abstract and different in purpose. Instead of finding a hidden alternate level exit when you blow up the reactor, you can find a secret level entrance as a normal secret in the regular levels at any point. Secret levels often barely feature any enemies and aren't difficult to fight in, but they're more difficult to explore because of all the switches and twisting passages and secrets involved. They have more of that "secret level" feel to them, where the levels themselves are quite silly. One only has you fight against enemies who drop bombs and run away from you, the other is an elaborate door puzzle, the other is a frantic rush featuring multiple reactors where destroying reactors adds more time to the self-destruct countdown. The purpose behind these secret levels is to stock up on shields, ammo, and cloaks/invulns, and then go back to the level you came from. There's a secret level for each episode, and multiple levels can have entrances to the same secret level. Only destroying the reactor makes secret levels permanently inaccessible, but since you don't need to blow up the reactors to exit a secret level, that's not much of a problem.
I'm not a huge fan of how these secret levels are handled, because they can imbalance the regular levels rather strongly if you can come out swooping fully cloaked, fully invincible, and fully stocked, just like that. Whether the levels were designed and balanced around the presence of secret levels is anyone's guess, but I'm imagining that the secret levels came first and that the levels in that episode would take the secret level in mind. If you're a completionist, it's rather questionable whether you really need to complete these. I just prefer more regular secret levels and hidden alternate level exits because they're more consistent with the pacing and structure of the levels. At least these secret levels have some unique concepts to them.
The new weapons introduce a lot of new interesting things to combat. Most of the new primary weapons are essentially supercharged versions of the other weapon bound to the same key. The Helix Cannon fires a spread of five energy bolts, much like the Spreadfire, but drains you energy very quickly, and isn't very useful at long-range. But close up the Helix Cannon absolutely SHREDS. As an alternative to the Plasma Cannon you have the Phoenix Cannon, whose projectiles bounce off walls and can be used to hit enemies around corners, but it also drains more energy than the Plasma Cannon does. The Omega Cannon fires an incredibly powerful homing ray, but it has its own internal energy supply which runs out very quickly and needs to regenerate a while before being able to fire again. Unfortunately the Omega Cannon is rather unreliable for longer fights, and isn't placed that readily for you to pick up and use in the levels, which makes it rather useless if you play with cold starts. Fun fact, the Omega Cannon was widely banned in multiplayer matches because of not only how OP it was, but also because it would create tremendous amounts of lag.
The existing weapons have also seen some changes. The Fusion Cannon in particular has been nerfed rather hard in D2, it's nowhere as powerful as it used to be. I never used it anymore. The basic Laser can now be upgraded to level 5 and even 6 using Super Laser boosts to keep up with the ongoing power creep. Though I'd say the presence of Super Laser boosts makes any basic Laser pick-up for Lvl 1-4 rather redundant. At least Super Laser boosts make starting off with just the basic Lasers easier and less of a hassle to level up by introducing Super boosts.
That leaves the Gauss Rifle, which is going to be your main workhorse weapon of the game. It's hitscan so enemies can't dodge your shots, it's got its own (often) plentiful ammo supply, it has a waaay higher DPS than the Vulcan, and basically it's the most overpowered weapon in the game. There's rarely no reason to ever not use it. The primary weapon balance in Descent 2 is entirely borked because of the Gauss Rifle alone. The presence the Gauss Rifle varies from a level-to-level basis and whether they do decide to hand out the Gauss Rifle and enough ammo for the damn thing. Which is most of the time. The levels which don't present the Gauss end up being some of the most challenging, and there's only one level in the entire game (L18) which has a secret containing a Gauss Rifle and three vulcan ammo pick-ups, and that's all the ammo you get for the level, for the rest you have to make do with energy weapons. The superiority of the Gauss Rifle is further enforced by the Energy/Shield Converter, which converts surplus energy into shields. So to not waste any energy and thus potential shields, you want to be using an ammo-based weapon, which in this case is the Gauss Rifle. The Vulcan had its niche in D1 for being hitscan but comparatively low damage, but the Gauss Rifle completely triumphs over anything else, which is a shame.
The new missile types are more balanced at least. There's Flash Missiles, which temporarily stun nearby bots (which is visualized by having bots spin around like crazy, which looks hilarious), and allows you to get the drop on some robots around a corner more easily. Unfortunately it's rather underutilized rather on in the game. There's Guided Missiles, which are missiles which you can directly control to go anywhere you want, which is extremely useful for hitting dangerous targets outside your field of view. Mercury Missiles are like Concussion Missiles, except MUCH faster, making them actually useful in some of the more open spaces in the game. Earthshaker Missiles are the most powerful weapon in the game, so powerful that the whole level will shake and lights start to flicker if it is detonated. Usually everything nearby is killed in the initial blast, but if it hits a wall it will send out a cluster of homing mega missiles mopping up everything else nearby which did survive. Needless to say, these are incredibly rare. Smart Mines are the rarer but infinitely more useful alternative to Proximity Mines, because upon detonation these will send out a cluster of homing energy globs as if it were a Smart Missile, killing all nearby bots. You can perform a lot of clever tricks with these, and they just work much better as a trap, in D1 you had to place several proximity mines in front of a trap door to kill all the enemies inside, now you place a single Smart Mine.
Most of the new missile types are very welcome additions and don't make the existing missiles useless (except Concussion Missiles which were largely useless to begin with), though I'm not too fond of the impact Guided Missiles had on the game. Descent 2 features several secret areas behind grates you can't pass through, but you can fire a Guided Missile through the cracks of the grate and send it crashing into a nearby switch to open the aforementioned grate, and collect your spoils. Not to say these aren't inventive, but the holes in the grates can be incredibly fiddly to pass through, which makes them unnecessarily frustrating. Your supply of Guided Missiles is limited, so if you do end up missing you're most likely going to reload a save and try it again instead of wasting valuable ammunition. To make matters worse, to get a proper angle at the grate so your missile can fit, levels rarely ever give you enough space in front of the grate to let you shoot it in a straight line, meaning you'll often have to hover in front of the grate, so if you miss and the missile collides with the grate you'll end up damaging yourself, which further pushes you to savescum this little pseudo-minigame.
The ability to hit enemies with Guided Missiles without exposing yourself tends to be sometime taken for granted, as occasionally levels pit you against dangerous enemies placed in rather bullshit positions, where you're expected to destroy them with the Guided Missiles, but there's often no way to know to know these enemies are there beforehand. Just because you can deal with it safely doesn't excuse the trial 'n error that goes into memorizing these tricks and traps which completely fuck you over at first but are absolutely elementary to deal with once you know about them. Annoyingly, enemies can sometimes magically figure out your position if you send a Guided Missile whizzing right past them. The idea is interesting, but the impact they have on the game isn't what I'd consider a net positive. Moreover, they also slow the game down tremendously by having you manually control several Guided Missiles deep into enemy territory.
Now the enemy roster is where Descent 2 truly triumphs over Descent 1. Whereas Descent 1 would feature a lot of reskins of existing bots with more souped-up stats, Descent 2 barely has any of that. And there's no fucking Class 1 Drillers or Red Hulks either. On top of that, Descent 2 bestiary is much more varied in function, visual design, and behavior. ITDs are small agile fuckers who shoot a stream of very fast but weak bullets, and are best destroyed with a Homing Missile or Vulcan. On top of that they can also alert their bigger ITSC brothers to come chase you down, which are bigger ITDs who can fire missiles and fire an ITD stream of bullets simultaneously. Smelters fire bouncing projectiles which makes facing off against them in narrow tunnels incredibly dangerous. The new Diamond Claws are much more aggressive, but also have the ability to short-circuit, meaning that if you shoot them with energy weapons they will shoot homing energy blobs back at you, which makes fighting them in enclosed spaces even more challenging. There's little Sidearm Modula buggers who can fire Flash Missiles to blind you. There's Seekers, who can snipe you from afar with the aforementioned Mercury Missiles. E-Bandits will drain your energy if you let them get close. Omega's are suicide bombers. There's even the Boarshead, who fires Smart Missiles which can hit you from behind with the group of homing energy missiles if you do dodge the missile itself. As usual, there are also some cloaked enemy variants.
Some of the D1 oldies are present again, but in a nerfed state. The Lou Guard functions identically to the Red Hulk, but the turning radius and acquisition cone of Homing Missiles have been considerably nerfed in D2, so they're much more fair to fight even in close quarters. Bulk Destroyers are essentially Class 1 Drillers, but way less aggressive and have a much lower fire rate and damage output, which makes them considerably more bearable to deal with. That doesn't mean I'm happy with hitscan enemies in a game like Descent, I'd much rather they be pseudo-hitscan, or only attack with (pseudo-)hitscan when they get close enough. In the end-game you will face an ungodly fusion of the Spider and a Missile Platformer, which spawns a random amount of little buggers on death. How I feel about them depends on how they are used, Platformers and their like are no fun in close quarters because the backblast resulting from missiles you did dodge then exploding on the wall behind you feels rather unfair (thankfully missile launcher enemies are used less often in D2, with the exception of the aforementioned Seekers sometimes being placed very close up).
Then there's the fucking Thief-Bot. As the name implies, this dickass can steal your shit and then fly away like a little bitch, taking the top spot of most annoying enemy in the game. It has a ridiculous amount of health and erratically moves around, making it incredibly difficult to kill unless you manage to trap it, after which you can kill it to take your shit back and get you some bonus shields. It's pathfinding is very efficient and can even utilize secret areas to get away from you. The Thief-Bot is the only robot which can see through your cloak, it can also steal your cloak and invincibility. Thankfully, it cannot damage you but only steal your weapons, and there's only one in the levels it appears in. That said, I do not hate it (I do hate it, but I do not wish for it to not exist (I do wish for it to not exist, but I think it adds something interesting to the game)).
The Thief-Bot adds a lot of unpredictability to the game whose AI can already generate many unpredictable situations, the unpredictability which I consider to be Descent's one of the greatest under-the-hood features whereas other contemporary first-person shooters are somewhat too static. Now you'll have to worry about this thieving cunt coming around to steal your precious Gauss Rifle, which would then leave you to improvise your way through. Chasing a Thief-Bot down is very likely to be exhausting. It's not like you can't do anything about the Thief-Bot coming to rob you. When the Thief-Bot sees you have your back turned towards it, it will slowly creep up on you, and while it's creeping up you can hear an ominious humming from behind, alerting you to its presence and giving you a chance to shoot at it so you can tell the Thief-Bot to fuck off. Of course, this can be challenging to do in the midst of combat where you've got other things to worry about. So in Descent 2, you always have to stay on your toes.
Something you could technically do in D1 but not really in practice is circling around an enemy to hover behind its back, which usually applied to larger enemies with slower turning radiuses. However, enemies in D1 were often placed with their back to the wall and their firing range overlooking you, which made this rather unfeasible. But since levels in D2 tend to be somewhat more spacious and larger enemies aren't impossible to deal with without cheesing them, you can avoid a Lou Guard or Smelter's line of sight entirely by just circling behind them, which feels more satisfying to pull off given the pseudo-dogfighting nature of the combat in Descent (in Multiplayer anyways).
The ITD/Red Hornet/Spawn/Sidearm Modulas can be tolerated on cold starts provided you have a Vulcan or at least some homing missiles to deal with them. Trying to kill one of those with your starting LV1 Laser is like trying to eat soup with a fork. They're too damn small and too damn fast for your laser and its terrible area coverage to hit them in open areas. And sadly some levels do throw them at you at the very beginning (the final level has four of them ambush you the moment you start the level). Just give me a Spreadfire at the very least. Given how levels should be tested with the default starting loadout since you can lose all your weapons if you destroy a reactor but don't make it to the exit in time, I find it hard to believe anyone at QA could tolerate these guys at the start.
One thing I always disliked about games such as Painkiller or Hexen or Amid Evil which refresh the enemy bestiary every four levels is that the cool interesting enemies don't get used again, or at the very least appear as a reskin. It's a waste of resources and level design potential. Now Descent 2 kind of does this, but even enemies introduced earlier on will continue to appear in later levels, such as the Thief-Bot, Diamond Claw, and Lou Guards. The underlying idea seems to be that if you're in a ice level of sorts, that you will face blue ice enemies such as Ice Spindles and Foxes, and in red levels you face red or brown 'fire' enemies such as PIGs (there we go again with the pig references) and Beepers. I guess that makes things more visually coherent, but I don't really think this should matter that much. I'd rather prefer an interesting combination of enemies no matter their visual theme. Though new enemies being regularly introduced over the course of the campaign keeps things fresh, having the final batch of new enemies barely cooperate with some of the pre-existing enemies is a bloody shame.
Every fourth level you'll face off against a boss enemy instead of a reactor, and these bosses are big dudes which can dish out a lot of damage. D1 had only 2 boss fights, this one has six. Much like in D1, the bosses in D2 can spawn additional enemies and also teleport around (probably to offset not being able to move as freely because they're so fucking big), and annoyingly they can also teleport behind you or in your face, though their target destination seems to be entirely random. I can't say I really dig the bosses, but they suit the exploratory nature of the game well enough where the arenas you fight the bosses in often have secret passages containing cloak and invincibility power-ups to make the fight easier, so the bosses are not just "shoot at it until it dies".
The first two bosses are easy enough and not really worth talking about. The third boss is slightly trickier because it fires Mega Missiles which have a large blast radius and home in on you, but the arena you fight this boss in is large enough for you to safely snipe it from a long distance (provided you don't get an unlucky teleport).
The fourth boss is considerably more anal, because it can fire homing Flash Missiles with D1-levels of turning speeds, meaning that fighting this boss head-on is fighting with a completely white screen. However, there's a room in the arena from which you can safely snipe the boss without exposing yourself. But it doesn't teleport on its own, you need to lure it out by hitting it with a Guided Missile so it can teleport into a position from which you can actually safely shoot the boss. This one sucks rather hard, on Insane cheesing is the only option if you don't want to get blinded to death.
The fifth boss is inexplicably completely resistant against ballistic weapons such as the beloved Gauss Rifle, meaning you need to kill it with energy weapons (and the only way you'll learn this is by looking up information online, the abstract-ass weapon resistances are barely communicated in-game at all). However, the arena in which the fifth boss is incredibly narrow and small, giving you no room to dodge its short-circuit homing energy globs, hitscan rifle, and Mercury Missiles. Save for the secret level (which is bugged on my end, for some reason I don't retain any of the items or power-ups I picked up in a secret level when I exit it), there's no Earthshakers or Invincibilities to make it easier on you (Shakers count as energy weapons for some reason), so the most surefire way to kill this boss is to hit it with the Phoenix Cannon and rebounding shots off the wall into the arena without exposing myself. And since the boss has a lot of health and the Phoenix Cannon drains energy quickly, you'll have to spend several trips to the nearby energy center to recharge. This one sucks too since you'll have no choice on Insane but to cheese it, but at least the boss model looks pretty cool.
The final boss is completely invulnerable save for a weak spot on its back, which you need to penetrate with Earthshaker Missiles. However, the boss itself primarily fires Earthshakers, meaning that if you don't have an invuln you will die and if you don't have a cloak you will be literally shaking. Thankfully there's enough Shakers placed in the level itself and enough power-ups in the boss arena. While the idea seems to be to fire several Shakers into its ass, you can actually get by with just one. Paradoxically, a direct Shaker impact deals less damage than all of its bomblets hitting a single target, and bomblets are only spawned if the Shaker hits a wall. So it's easier to fire a Shaker at a wall behind the boss' weakspot, have the bomblets home into the weakspot, and then finish off the boss with your laser. Normally most things die in the initial blast so you don't even notice. Given the amount of Earthshakers I'm inclined to believe the designers intended the player to kill the boss with direct Shaker impacts, an oversight perhaps? This boss is more of a puzzle than anything this way, and actually rather underwhelming once you realize how to beat it. Weirdly enough, the game ends directly when you kill the boss, no escape sequence or anything even though there is an emergency exit present in the final level.
Bosses in a game like this could challenge your ability to move with a plethora of interesting to dodge attacks, and with the standard enemy AI, I can imagine you could make an interesting boss fight if you gave a boss more routines for what to do depending on your (relative) position and range, and more phases to challenge the player's aiming and dodging skills. As it stands, most of the bosses are given overpowered weaponry which makes a regular dogfighting approach you would use against a normal enemy out of the question. The teleporting shtick is too random for it to be really fair, there's nothing preventing from the boss teleporting behind you or in your face, with no way to reasonably defend yourself against it. The first two fall into "shoot at it until it dies" territory while the rest fall into "cheese or die"-puzzle boss territory.
I find that the final Puuma Sphere episode does kind of drop the ball, as the levels revert to D1's dickassery of cheap traps and very narrow corridors with Smart Missile-launching Boarsheads and Spider Platformers. It's got none of that exploratory goodness of Brimspark or Baloris, and even geometrically the levels in Puuma Sphere look like Descent 1 for how simple the geometry is. Puuma Sphere also features some of the hardest levels in the game, which is unfortunately achieved through the aforementioned dickassery. L23 is strangely one of the easiest levels in the game for how ridiculously open it is and lenient with Gauss Rifle ammo. It also shows that Boarsheads work much better in larger areas since you're given plenty of room to dodge their Smart Missiles and the homing energy globs coming up from behind you. Unfortunately this is the only level where the Boarshead is used in this way. I wish Boarsheads were introduced earlier on and be placed prominently and large open areas, because of how much I like the idea of dodging smart missile globs from behind given enough space. Personally I think introducing no new enemies at all for the final episode and having instead the entire cast appear for each level would let you do much more creative things with the level design on top of instilling a sense of closure with having each bot wish you farewell (with their bullets). The difficulty curve of D2 does increase exponentionally towards the end, so most of the game isn't really like this.
The (MIDI) music this time around is done by one guy called Dan Wentz. In my opinion, these tracks are some of the best in the Descent canon, but as a soundtrack it's way smaller compared to Descent 1. Aside from a menu, briefing and ending theme, there's only four level themes reused throughout the game, compared to D1's 22. Though this kind of fits since the singleplayer is split up in episodes of four. Now, this comparison isn't entirely fair. D1 had a longer development time behind it and a whole team of Interplay composers, whereas Descent 2 had the development time of slightly over a year with one guy doing the music (and Mark Morgan contributing music for the cinematics). The alternative to the MIDI is the Redbook soundtrack, which delivers studio-quality industrial music certainly fitting for Descent (including some music by Skinny Puppy and Type-O Negative), though much like the D1 Redbook soundtrack I found it to be too loud for a game like this, and the MIDI songs for D2 are already pushing it. Even so, it's certainly not a bad alternative to the MIDI music.
I guess this sounds like more shitting than praising, though most of the praise I have for D2 I noted for D1 in a previous post about D1, and don't feel like repeating myself too much since D2 is in a lot of ways very identical to D1. However, I do consider D2 to be the superior game because of its superior bestiary and weapon line-up (even though the Gauss Rifle unbalances everything like hell) and more fleshed out level design. The AI's new ability to lead shots did a lot to spice up combat. Save for the weapon balance and soundtrack, Descent 2 takes everything D1 does and does it better, you can't ask more from a sequel.
There's also a PS1 port of Descent called Descent Maximum, which features its own original set of 20+ levels made to play using the Descent 2 enemy set. You can find a PC conversion of Maximum and play the levels on PC. The Maximum levels are much smaller in size and scope, probably to fit the PS1's constraints. Though small levels like these are kind of fresh after being only able to finish one level per day. I haven't finished Maximum yet, but there are some interesting levels in here, even though some of them are not that good. There's also the Vertigo expansion pack for Descent 2, which features twenty new levels and new enemies, though I haven't gotten around to playing it (or installing it, I'm having trouble finding it to begin with). I hear Vertigo is even better than the D2 campaign. I don't think I'll be able to clear all levels on Insane before Overload releases, though.