I quit Star Trek: Bridge commander. And actually got a refund for it, the first time I did so for a game bought on Gog that I had already downloaded and played. Didn't enjoy the game at all. I disliked how heavily scripted it felt, there was very little in the way of real choices. Even Starfleet academy, which had plenty of flaws and was also heavily focused on combat, offered more in this regard, at least there you could occasionally choose between dialogue options (sometimes with real effect). And the combat was just atrocious. I guess I was doing something wrong, but controls felt unresponsive to me and there was little feedback to your actions. I got until early in episode 2 where you have to disable a Ferengi freighter...which I tried three times, but failed to do, even though it ought to have been a trivial task. I tried disabling its warp engines, but often seemed to do no damage at all to the ship, despite scoring hits on it (and trying to keep up continuous fire by manouevering my ship around, so phaser bays could be re-charged). Or at least I thought I was hitting it, difficult to tell given the lack of clear feedback. In any case a pretty frustrating experience.
imo this game is only good for hardcore Star Trek fans who are fine with heavily scripted and quite restrictive gameplay, as long as the game is set in the Star Trek universe. If you're at most a casual Trek fan, better look elsewhere. I've enjoyed various Star Trek games in the past (really like 25th anniversary and Judgement rites, have also had fun with Starfleet academy and the Elite forces), but this one wasn't for me.

battlefield 2042 open beta , didnt even start :O

Wolfenstein (2009) on Linux via Wine
Ran into a game breaking bug that I cannot get past no matter what I do, thus I'm throwing in the towel. I tried it out on the PS3 quickly but realized it's locked at 30fps, so that's a no go.

I decided to go through my Wolfenstein backlog and wanted to start at the 2009 one because I don't think I'd enjoy any of the ones before that. Hopefully the others perform better.

As soon I started the game, I noticed the Singularity similarities very quickly, which makes sense given Raven Software is the developer for both games and Singularity was released very shortly after Wolfenstein. I actually preferred Singularity to Wolfenstein mainly because it felt more polished and and seemed like a tighter package.

Now that I've fixed Wallace & Gromit Episode 2, on to that!

Playing Star Wars: Jedi Knight: Mysteries of the Sith and I think I'm going to just walk away from it. I had played Jedi Knight a while back and couldn't remember what I thought of it, but playing this game and getting up to the level 12 "fight your evil self" bit reminded me: The lightsaber dueling SUCKS! The rest of the game is nothing amazing, either, once you get past the Lucasarts polish it has, but they absolutely hadn't figured out FPS melee combat at this point. Tired of chopping away at this bitch over and over and over and over and over and over and over only for her to not fall down.

Quit another two.

Shadow tactics: Blades of the shogun...in Level 8. I probably would have been able to finish it, but I felt the game was getting unfun at that point.
It's mostly a good game, but for me it didn't manage to surpass the original Commandos. Frankly, I think its levels are too big. And the story didn't do much for me, found some things downright weird. There's a young girl in your group who comes across as kind of naive...but cheerfully kills dozens of enemies. I could tolerate the violence in the Commandos games with their WW2 setting, but this creeped me out a bit.
There are special challenges (called badges) for every level, but tbh I found many of them ridiculous by their descriptions, you'd have to play in a pretty contorted way to finish some of them.

Also just quit Mafia. The infamous racing mission did me in, even on very easy it seemed overly frustrating, and I'm no longer willing to spend hours on such a stumbling block in a game. Absolute bs design. If I hadn't recently refunded Bridge commander, I'd try to get a refund for this as well.

"Quit" The Legend of Heroes Trails in the Sky and The Evil Within when my computer died and I lost the saves. Lost a bunch of other game saves as well but those were the two that I was actively playing and would have finished soon. I'll get back to them eventually but dread the thought of replaying them right now.

Pity to abandon such a great game. Maybe try this trick:
https://www.gog.com/forum/general/special_sale_b2k_games_up_to_80b_0ceb9/post32

I used that when I played Mafia. Do you know if the Remaster tweeks it?

Don't know, haven't played the Remaster. I don't even know where exactly that shortcut is. I've read about it after playing the game.

thx, I actually tried again and finished Mafia yesterday (didn't use an exploit for the race, just played on "very easy", which was still annoying enough). I enjoyed much of it (story is definitely very good by videogame standards)...but still think that racing mission was terrible, baffling choice to include something like that in the game.
Probably doesn't work in the Remaster. But tbh I don't know if the remaster is worth it, it seems to change A LOT in missions and also in dialogue/story (compare the ending scenes on Youtube, the remaster changes the utterly bleak ending of the original into something much weaker).

Call of Juarez: Gunslinger
Like Bound in Blood before it, Gunslinger suffers from a lack of contrast, making it rather difficult to see what's going on and some gun fights were plain hectic and not fun.

Mirror's Edge
The parkour seems to rely on perfect jumps and positions and even being a bit off on grabbing a pipe/pole results in falling an dying. Not the best experience.

Quit Full Throttle remastered. Had gotten as far as the road wars section, but that seemed kind of annoying, and I didn't care much for the game anyway. Couldn't relate to the story and characters at all. Very weak game imo.

Getting really close to quitting Stealth Bastard Deluxe. Its a hard game sure but it's not something you get better at. It's a game of memorization and precise timing. And finishing a level is so unsatisfying. It doesn't make me feel clever like a puzzle game. It just makes me feel like I got lucky with the timing and I've been wasting hours of my life.

Carrion
Controls on a controller are horrendous and since I only game on a couch with my PC hooked up to the TV, this is a deal breaker.

Duke Nukem Manhattan Project
Played 2.5 levels and I already felt like there was no challenge or interesting thing keeping me around.

That reminds me that I gave up on Butcher recently. I really wanted to like it, but I found it really hard to follow the action when things got hectic because of the miniaturized graphics. I've never gotten along with that "very tiny" look.