AYUP. ATI also doesn't seem to like Aarklash or Sang-froid. I have no idea what it is with this card and getting pissed off at everything.

Quest for Glory is one of the sierra games with the least amount of hotline requirement, and one that you can go through blindly, assuming you do of course talk with the people in it. On the other hand, the rest of the quest games (police, king's, space) are notorious for their design, but QfG is quite different.
So you can imagine the 13 year old me who first played Quest for Glory and got introduced to the other Quest games later on...

Syndicate - I honestly still have no idea how to play this.
Guilty Gear X2, Pharaoh Gold, Caesar III, Disciples 2 and Temple of Elemental Evil, some of the Myst games - They simply refuse to run on my PC.

Well, there are a few that I thought I would enjoy more and in consequence I wished I hadn't bought them for the regular price, but in general I don't regret having them in my collection, because it was still interesting to try them and who knows, I might change my mind about them one day. Those include e.g. Omikron, Fahrenheit or Inquisitor; games I don't hate but that I have several issues with and that disappointed me because I expected more. But that's also because they have great premises and I respect them for that alone. I guess I'm just mad at them precisely because they could have been far more interesting games than many in my collection that I just don't care enough about to be disappointed.

As for games I really regret buying, I dunno. Maybe Evoland, as it seems so bland I wouldn't miss it if it was removed from my account. I didn't expect much of it, I had even played a bit of the flash version that preceded it, so I knew what I'd get, but it still managed to surprise me by how boring it is. Could be I'm biased though, as the game's moving from Zelda-like gameplay to turn-based JRPG random battles quite quickly, and I much prefer the former (really hate the latter).

And possibly Richard & Alice. I played all the way through it, and even though it's not that long I kind of regret the time spent on it and I don't get why others praise it so much. IMO it's got neither a very mature or interesting story, nor exceptional storytelling or enjoyable gameplay. I wouldn't mind the simple graphics if I could find anything worthwhile in the game, but I can't. I've played so many freeware adventures that were more fun to play and more professional in looks and gameplay, so I don't quite get the spotlight on this one.

I don't get disappointed easily. I may not be entirely happy with a game, but I usually don't excite myself too much about a game to avoid disappointment. Still, it has happened with three games here on GOG.

Divine Divinity. It was the whole reason I came to GOG and it ended up being boring, filled with difficulty spikes, and uninteresting plot-wise. It has a few redeeming qualities, sure, but not enough to make me enjoy the game.

Tiny and Big: Grandpa's Leftovers. I was immediately captured by the graphical style, and after playing it I still consider it to be the game's best quality. The puzzle solving was also pretty interesting; a little finicky, perhaps, but overall pretty fun. Unfortunately, everything went downhill not too long into the game. See, you can die in this game, and it will happen a lot. Those once-acceptable finicky controls become infuriating, and the checkpoint save system doesn't do much to help. Add to that an uninteresting story and humor that falls flat, you get a good-looking disappointment.

And now for the big one. I might get lynched for it, but whatever.

System Shock 2. Almost everyone on GOG sang this game's praises prior to its release here. It was the pinnacle of gaming, a true classic, one that every gamer should own. I was, understandably, caught up in the hype (for lack of a better word), in part because I had heard about this game's awesomeness even before coming to GOG. When it was finally released, I knew that one day I would own it. When the winter sale came along last year I bought it. It was the first game from that sale that I downloaded and played. I started it up, went through the opening bit, waiting for the gaming glory to fall...

And I was utterly disappointed. It's not a bad game, exactly, I just didn't find it to be anywhere near the masterpiece it was made out to be. The whole RPG system isn't very good, the worst part being the horribly imbalanced classes. The actual gameplay is hardly satisfying, and the plot, while intriguing, ultimately falls flat. (SPOILERS) SHODAN is an interesting character, but her voice is annoying and she isn't really that scary. She was also a horrible end boss. Also, I wasn't a big fan of the alien things (and to be honest, I felt that the inclusion of spiders was unnecessary and a cheap attempt to scare people who are afraid of spiders). The ending was pretty bad, too; I really could have done without the "Nah." And the cliffhanger didn't make much sense.

Cryostatis

There are some bugs that you need to use console commands to bypass, but that's not the killer.

The worst is the final battle.
The game is a huge resource hog, and the final battle is in a large area, bad lighting, and horrible controls.
Aiming is a crapshoot at best, and the lag is absurd.

I have a fairly robust system, but even turning down/off most everything still didn't help with this one.

I tried off & on several times over the past few months to finish out the final battle and finally just uninstalled the thing as a total waste of time.

Certainly. I was looking for a nice point & click adventure and some people recommended:

Myst: Masterpiece Edition...

It was terrible and horrible. I am okay with outdated graphics with an old game, if it were actually a game. I found it boring and dull.

Well I've had a reason for creating this topic :-P Still, there is far less people disappointed in the game than I have expected based on the hype.

Many interesting posts here, I'm a little bit surprised to read that Theme Hospital or praised SS2 (although I've never played it) could be disappointing.

Anyway, I haven't forseen that 5 star game could be just indifferent to me either :-P

Biggest disappointment for me was easily Total Annihilation. I really enjoy RTS games: Warcraft, Starcraft, Warlords Battlecry, Homeworld, Dawn of War, etc. So I start looking into TA, praised as one of the best RTS games of all time. I absolutely hated it.

I suppose runner up would be Syndicate. It isn't terrible, its just that the game is terribly slow paced and bored me. Speed it up by about 50% and I suspect I would enjoy it a lot more.

I have yet to play most of the games on my shelf though. I don't think anything will disappoint me as much as TA, but there's still plenty of room to be worse than Syndicate.

For me it'd have to be the Icewind Dale games (sorry!). I never played them back in the day and when I recently tried to slog through them, I discovered that they're the kind of game where you can only really succeed if you already know exactly how to play them... If you happen to set up a party with the wrong combo of classes or don't put your skill points into exactly the right thing as you level up, you'll find yourself screwed and constantly getting owned. There's making a game difficult, and then there's making it so you are doomed to failure unless you do things a certain way. This was pretty much the least fun I have ever had playing any games, and I put about 20 hours into each of these, so I gave them more than enough chances!

Aw, dammit- I have both Tiny Big and Total Annihilation, so now I am expecting the worst from both :\

But for me it's Lucius- there's just something missing from the game (a personality, maybe?), so you end up getting bored with it really fast. There are also other issues, like having to kill someone in a specific manner, which confines the gameplay, and that's also boring and tedious. Basically, like others I was hoping was a Hitman type game, but for this game, I wish I had read the GOG reviews.

The spin-off, American Nightmare, is a much better game. The combat is better, the world is more open and the plot isn't a slobbering tribute to Twin Peaks and Stephen King.

Interestingly, when I replayed Alan Wake, I appreciated the plot a bit more. If only it wasn't so blatant all the time -- I think they could have had a much better job with a bit more subtlety. Most of the first playthrough was me going, "Yeah, I get it." There was no need to point the references out every time.

I couldn't find American Nightmare enjoying - it's one level played over and over again (like 3 or 4 times?). Maybe not a big one, but definitely disappointment.

Well, in a way it doesn't really count, but - The Bard's Tale. I had it on console when it came out and knew I didn't like it, but I wanted the three original games that came with it.