The problem with such a topic for me is that I mostly play or replay older games, and in the latter case these are always damn good games (otherwise I would never replay them), so it's hard to even handpick a few of the best ones. I'll try with stuff I don't come back to regularly (Rimworld, ONI, Factorio etc.), mostly aren't well known classics (like the RE games I replayed or Homeworld etc.) or actually played/finished for the first time and thought I have something to say/sperg about the experience.
Dark Souls - finally finished it, two prior playthroughs were abandoned around finishing Anor Londo. Last one I was stuck in the painted world of Aramis with a broken weapon and no repair kit thingy leading to abandoning that playthrough, but if I read the wiki/a guide I would have realized I could have just bum-rushed to the exit without fighting any boss... Anyway Anor Londo and the mentioned Painted World are kind of the drop off points after which the game either gets stale or the areas/bosses seem mostly phoned-in/rushed, and with the exception of the four kings and final boss not that challenging anymore. That and the gameplay gets stale at that point. Definitely had fun with it though, I like how the game's combat rewards patience and a cool head, and also how "impactful" the melee thwacking in it feels.
Days Gone - I did a longer post on my impressions in the topic about it. Basically it was a comparable open world experience to the Mad Max open world game, also had the problem of eventually getting stale/being too long. That and the game was rather easy. Still I liked the biker theme and oregon wilderness while on a bike, and the enemy camps were far more fun to clear than in Mad Max due to the (crude) stealth mechanics and I guess better combat. I don't like the batman: arkham series awesome button punching combat that Mad Max has, and the batman games at least usually had combat as a stealth failstate rather than only solution to most encounter, which unfortunately is the case in Mad Max. In a few ways Days Gone feels like if the Last of Us was openworld instead of a corridor-shootan game long escort mission (i mean they were both Sony exclusives for years, make sense it was the inspiration), and had bikers. Killing nesting hordes of dozens and sometimes even hundreds of zombies was a nice gimmick. Main character felt too angsty/emo at times, but that could be explained by his PTSD or something I guess.
Ecco the Dolphin (Sega CD version) - a 16bit diamond in the rough, a bit more polished in the CD version, especially regarding the difficulty/frustration factor since there are checkpoints in levels now and the game has quite some bullshit sections where repeating the whole level because of them feels extremely cheap. I tried the cart version first and honestly the damn redoing whole levels part is a major pain, and now after finishing the CD version I can't imagine how the hell people could not drop the cart release due to some bullshit like that one bossfight at the end of a very fucking hard and long level late in the game. Also the CD version has a few new extra levels (ab)using the new checkpoint system. As a game this is basically a rather artsy and kind of twitchy/reflex-based game where you try not to drown as a dolphin (they don't have gills, duh) navigating underwater mazes, doing puzzles mixed with a science fiction plot about rescuing your dolphin bros. The whole concept feels very fresh and original even today. It has the weirdest difficulty curve I ever experienced, the first two-three real levels are the hardest part of the game, then suddenly the difficulty drops off a cliff for like 10 or more levels, until the very end of the game where it gets again quite hard in the last 3 levels. The last two levels are autoscrolling annoyances though, so partially could be considered fake difficulty, especially the penultimate one. Great music, if you like synthy/ambient oceanic (a bit vangelis-like) themes the CD version's soundtrack is something you should check out, it is easy to find on youtube. I like working or taking a power nap with it playing in the background, good vibes man.
Warhammer 40k: Squad Command (PSP) - an interesting turn-based tactical game with a very nice tactical combat system doing grid-less movement, proper action point system with X-COM (the DOS original) style reaction shots from leftover AP, 3d destructible terrain, 3d LOS/projectiles, 3d cones of fire and other incline. Didn't beat it yet. The main flaws of it IMO are that there is no unit persistance and each mission has an arbitrary available unit type pool. For instance you can't deploy scout marines and must deploy tactical marines, or you are forced to have one slot taken by a specific vehicle. You can however change secondary weapons. I would have preferred a more flexible system, like point-buy. Also due to lack of any kind of persistence there's really no penalty for doing not good or outright bad in missions (or reward for doing well), besides some score which I think is pure bragging rights without any gameplay impact.
Lord of the Rings: Tactics (PSP) - an obscure turn-based tactical game from back when EA milked the LOTR license, it's janky as fuck, besides low framerates there's for instance no top of the skybox (only horizon) and they failed to make sure the camera angles never show that
Still it has a decent rpg-lite system for upgrading characters with both +stats and skill/tiers available (you can increase attributes like STR or DEX even on Gandalf if you wish or buy skills), status effects, status effect resistances. The game has attacks of opportunity and zones of control, so mechanically it's actually a lot deeper than one would think a noname studio (seriously, can't find nothing on it regarding who the fuck they were and did) licensed cashgrab portable console tactical game with some FMV cutscenes taken from the movie trilogy would have. One would rather expect extremely shallow low-effort shovelware. Besides the obvious characters with their movie likenesses you occasionally control cannon fodder allies ranging from Rohan Riders to Ents.
Besides technical issues, the flaws it has are of course too many chapters where you are forced to use specific characters and not enough ones where you have freedom in that (for obvious story reasons but still, let me use Gimli more FFS). It can get a bit grindy at times, with you needing to replay missions, particular the optional ones that give you freedom over character choices, to get exp or gold (needed to buy skills and consumables) for characters that have to take part in the current obligatory mission. Also disappointingly it has ultimate abbilities that say for example "you summon ents", and you don't get the actual Ent units you got in prior missions to appear on the field to do your bidding as meatshields, rather it is like a final fantasy game style summon spell, where it's just a damage all enemies on the map spell with a "flashy" animation (which like the rest of the game looks rather meh and janky since they probably used borrowed assets from another EA LOTR game from the PS2 or something, and downgraded them to the PSP's level, badly). That and the evil campaign and character pool in it is rather tiny/meh compared to the good guy campaign, this feels even worse than a similar issue was in in the LOTR: Battle for Middle Earth's Evil campaign, despite both games having the same "storytelling/cannon" limitations influencing that.