There're a few games which kind of disappoints me and that I've put on hold and want to restart later:

- Tower Assault: I'm not sure why it couldn't grab me. Maybe because I played Alien Breed right before.
- Betrayal at Krondor: I don't like the graphics of this game.
- Darklands: there is no main plot that keeps me playing
- Eador Genesis: long campaign with every shard just a skirmish. After losing three times on the same shard I'm too frustrated to play on.
-Humans must Answer: collecting all 160 gold eggs for the second end is just frustrating.
- Ishar 3: after a game breaking bug I lost any interest.
- Master of Magic: maybe I'm just more into scifi or I made the mistake to play the first game on very easy. Either way it was boring.
- Miasmata: performance issues
- Neverwinter Nights 2: bad camera controls and playing as mage isn't fun if you stand at the front and are the first to be attacked.
- Nox: I finished it as fighter in the first play through and it wasn't very interesting.
- Silver: another well known game breaking bug (bell puzzle).
- Space Quest 4: dying so much isn't a problem if the game at least would run, load and save faster.
- Star Control 1+2: the combat controls are just not for me.
- The Temple of Elemental Evil: didn't finish it and after installing the Circle of Eight mod I wasn't in the mood to restart.
- Thief Gold: crashes. But that's a game I have on CD for years now and have already played it.
- Warlords Battlecry 3: somehow I lost the interest.

I'm very careful with my purchases, so it's very rare I will end up with a game I didn't like. The closest would have to be Forgotten Realms: Demon Stone, which I bought as part of the D&D Bundle (Containing many games that I liked). I won't go into reasons why I hated this game, because then I would be beating a dead horse. Suffice to say though, I wouldn't shed a tear if this game disappeared from my shelf. (And just hiding it doesn't count.)

You could also count Oddworld: Stranger's Wrath and Rise of the Triad (2013), because they stubbornly refuse to run well on my PC.

That sucks, I just installed it yesterday in WinXP and had no problems.

^This!!!

I haven't played most of the games I've bought yet. But I haven't been disappointed in any so far. I have lost interest in a few but this is very common for me. After completing QFG 1 & 2, I started 3 but never came back to it. There was sooo much conversing going on at the beginning, all I felt like I was doing was reading. And Baldur's Gate. I kept getting my ass kicked by the wyverns in some cave and haven't gotten around to trying again. I like the game, but I think the character I created was a mistake - tho there is no way I'm starting over. I'm also not a huge fan of the combat/magic system.

The only game that I really regret buying from GOG is Inquisitor. It's an absolutely horrible game. I really wanted to like it, but I couldn't. Life's too short to be wasted playing games that I dislike, so I gave up.

Inquisitor and Legend of Grimrock were my biggest disappointments.

Not good enough excuse. Shadow Warrior (2013) runs much better. So does Strike Suit Zero and Divinity: Dragon Commander and Aarklash Legacy and...
Look, I could be going on and on, but I would have appreciated it much more if they had decided to list higher requirements than the current ones. That way, I and others wouldn't be so horribly disappointed by the unexpectedly poor performance.

requirements jsut tell you what you need to run the game. even the recommended requirements are always a bit low.

That would be fine... except for the fact that both Shadow Warrior (2013) and Rise of the Triad (2013) have the same requirements. And Shadow Warrior runs fine on high. Rise of the Triad struggles on low. Strike Suit Zero actually has higher requirements than the both of them and it still runs fine on high.

yep strike suit zero is a very well made game. My experience is, that SW is a bit slower than ROTT actually. I have Ultra/Ludicrous settings on both and have constant 60 frames with vsync in rott (well except for big halls there its about 40+). and in SW it's a bit...well...lower.

Good question OP. In my case it was Broken Sword 2-4. I loved the first game and consider it one of the best adventure games of all times. So in a fit of passion I bought all the other three. I did finish #2 despite the fact it wasn't nearly as good as the first one. #3 is unplayable in my view because of the controls And #4 is simply a bad game that I never finished.

It taught me a lesson that games are just like movies... Just because the first one is good doesn't mean the sequels are.

I don't have any regrets this far, but i always read about the game before i buy, and I'm a bit picky too. ;^)
Independent video reviews is a good way to see if a game really is worth to throw money at.

I haven't played most of them enough for a definite answer, but so far "The Real Texas" and "Defcon" are the ones I most regret spending money on. "Defcon" seems decent enough, but you can't play it properly (not even in single player mode) unless you enter the serial key, which in my mind constitutes DRM. Wouldn't have bought it if I had known! This thing shouldn't be sold on GOG, as far as I'm concerned.

"The Real Texas" just seems like a total dud. I played it for maybe a half an hour and didn't find anything remotely enjoyable about it. It felt like the kind of indie game that gives indie games a bad name.

Quest for Glory 3 is the weakest title of the series. I love it for its setting, and how you get to learn more about Rakeesh and his people. But it doesn't feel as engaging as the other titles in the series do (and yes, there is a lot of talking going on). I understand why you lost interest in that one, but don't give up on the series. Or at least give Quest for Glory 4 a whirl. It's the best of the Glory games by far (see my earlier propaganda post on the subject :P)

Yes, I am a fervent Gloriana Crusader. I will spread the Good Word about the Quest for Glory series!

I got that free in the insomnia sales (but haven't played it yet) so I'm not too worried if it's a dud. However I had heard good things about it so I'll still be a bit disappointed if it's just no fun.

Perhaps it's one of those games that appeals to some gamers but completely turns off others?