Finished two playthroughs at different points of Early Access, so I'll give my thoughts. Again, this was played ~2y and ~3 months ago, so some things might have changed since then.
Combat: Very solid TB combat system. Every character in your troop has a set movement range per turn (can be increased when leveling up). Attacks can be used at any point without depleting your movement, so you can move half your movement, attack an enemy, and move some more. Most Melee attacks or skills engage a target, if it isn't already. An engaged target will take an opportunity attack if it moves, and can only attack the target it is engaged with. Attackign an engaged enemy from behind allows backstabbing/ambushing, and surrounding enemies makes them take more damage as well, allowing you to flank individual enemies.
Initiative doesn't really exist, for the player anyway. Once you enter combat, you and your enemy will take turns moving 1 character at a time, provided both sides have the same number of troops. If you are outnumbered 2:1, then for every time you get to move a character, they move 2. If you are outnumbering them, same rules apply. Bossfights are an exception. The order in which enemies attack is set at the beginning of each turn. If you are acting next, you can pick any character that did not yet act this turn. You can pick and choose your order freely, so by surveying the battlefield and checking on which enemy attacks when, their movement/attack range etc, you will want to plan the order in which you use each of your party members and take out targets strategically to minimize the damage you take.
Each character occupies a square, and you will not be able to move through another square that is blocked by an enemy, an obstacle, or a friendly unit. This can be a bit awkward at times, but it also allows you to utilize the battlefield to create choke points. Useful against larger enemies like most of the wildlife, which occupies a 3x3 tile instead of a 2x2 like any non-boss humanoid.
Many abilities require Action Points to use, and you can only have so many of them before they are depleted. Resting restores a certain amount of permanent Action Points (until you use them, ofc), while your characters can generate temporary ones that are lost after the battle concludes. If you plan on fighting many battles without resting, you'll want to manage your usage of these, adding another layer of strategy to each of your fights.
Overall its simple but also a lot of fun. If I took too much damage, it's because I didn't strategize and plan correctly. If a unit died, it's because I made a mistake.
Crafting: Crafting is great in this game. You unlock recipes in a bunch of different ways, and every partmymeber can learn a profession to craft and build items, from potions, poisons, traps, to armor, weapons, or tools that improve your resting. You can buy iron at the local market, or you can go out to some of the mines you discovered, and have your Miner hack away at some ore. Herbs found while travelling can be made into healing kits or weapon oils by your Alchemist, and your Strategist can craft items for your warband that can be used during camps, like meat drying racks, tents, items for your ponies etc. If you don't like crafting, you'll have a hard time in this game. Some items are difficult to craft and barely offer any significant benefit. Blacksmithing is way too important. Some professions are barely developed.
Party Management/Exploration: Managing food, medical supplies and armor repair kits can be tough, especially early on. Gold is pretty scarce, at least on the settings I played at. You might not be able to repair everything fully at the start. There's a big world to explore, but your forays into some of the more distant places will be limited by your ability to feed and pay your warband. You'll likely stay close to a city because moving too far away from one, will spell almost certain doom. Once you've taken on some contracts, leveled a bit and acquired a few abilities that make your exploration easier, you will be able to go days or weeks without having to visit a city. It feels like solid progression throughout, and the mid-way point of the game is definitely the strongest part. Resting sometimes allows you to pick and choose party banter options with positive or negative side effects, or grant new traits or XP. Resting in your camp is the only way to generate Action Points, which are key to your success in battle.
Characterbuilding/Itemization: Theres a bunch of difference base classes, that can choose additional specializations once you leveled once or twice. These allow you to develop into typical archetypes, like Rangers being able to become proper Archers with an Overwatch like attack or Beastmasters which allow them to boost and buff beast-allies; you can catch wild animals you fight with ropes and train them, or shackle human enemies and sell them to the local prison if they're bandits, or try to recruit them. They all suck though, for the most part. The specializations decide what kind of armor you can wear, which is your main defense in not taking damage to your hitpoints, and heavy armor provides more "shield" as well as higher damage mitigation, i.e. a well geared heavy armor specialist can take some serious beating. Speciailization also grant additional skills, which can be used with Action Points you generate after a rest or through certain combat passive actions. Managing Action Points is critical to success in combat. Characters also gain traits through a variety of actions, that can grant bonuses or maluses to your combat or warband management. Stats are simple but mostly useful. Some only affect your damage, others like Willpower grant a chance to crit, and allow you to gain damage bonuses during combat or make the enemy retreat faster. The Stat system is definitely the weakest part in all of this, and leveling up is a massive power boost due to the gain in HP and stats.
Paths: Theres a few paths that are focused on Exploration, Crime, Combat, Crafting etc. that allow you to gain additional bonuses once you have accomplished specific tasks. Some of them are easy to get, others not so much, and they unlock more quests or passives along the way. It's a solid system, but needs some balancing. Ultimately it's just another progression system, but with added characters and questlines, it feels meaningful enough.
Contracts/Bounties: While there's a bunch of contracts, the pay is kinda shitty and barely keeps you afloat. They're also very random, and you might take care of some objectives that could have a bounty on them, but it simply didn't show up yet. Since a bunch of locations are one-time encounters, this feels like bad overall design, and you might meta-game around this on a second playthrough.
Difficulty: Difficulty can be great or bad, depending on what you expect from the game. The game has two settings: Everything level-scales, or each zone has specific levels. With how much HP and armor enemies gain by just having one extra level, level-scaling keeps a solid difficulty across the entire game. You can explore the entire world immediately, and whether you have a small or big warband, the game will feel somewhat challenging throughout.
Alternatively, you can choose the mode which doesn't levelscale, and instead each area has a level-range. Going back to a previous one allows you to breeze through the fights, and it's a great choice for a first playthrough. As there's no procedural generation, subsequent playthroughs might feel too limited or same~y as a result.
Loot: Sadly, Loot kinda sucks. With the exception of unique items, which can be found from bosses, in certain predetermined places, or through some quests, loot is completely random. And, for the most part, entirely useless. Crafted items are almost always better, and you will rarely use items dropped by enemies.
Replayability: As a result, the game isn't really all that replayable. While some or even most quests have two possible outcomes, they don't really change the world in a meaningful way. Unless you want to run a small warband on purpose, you'll likely end up having one of each specialization or character.
While these sound pretty damning, I still spent a solid ~100 or so hours on the game. It can get a bit same~y if you play it a lot in a few sittings back to back, but there's a lot of small sidequests and storylines to explore, so you won't really mind unless you want to min-max your crafting and gear. I would second some of the reviews, in that the game doesn't feel finished. Each of the already solid systems, as well as the bad ones, could be a lot better with just some minor improvements, and if the devs follow up on the feedback and their own ideas, this game could become a true gem. As it stands, it's still got a long ways to go, but the current product was well worth my money.
If you enjoyed Battle Brothers, you'll likely enjoy this.