I wouldn't want to do it, but since the matter is something I cannot do anything about, it's beginning to become increasingly apparent that the first game I'll be quitting this year is Omerta - City of Gangsters.

The reasons: I've encountered two separate game-breaking bugs (one on Georgia Ave, the other on Garden Pier). As I've learned, the Steam version has a newer patch than the GOG version, but they've had it for more than two months: it's as if the developer doesn't care about those with the GOG version. As much as I would like to complete the game, it's impossible in its current state. I hope us GOGers will too get the patch eventually, but to be frank, I won't be crossing my fingers. A shame really, because I genuinely enjoyed the game unlike many others have.

The only games I truely quit are MMOs and f2p games.
I did play Atlantica Online for 1 year, wasted a ton of money turning a +5 weapon INTO A +5 weapon.... quit there.
(how the game works, you can upgrade an equipment by 1 rank/level with an item from the MALL, and you have a 50% chance to fail, if you fail the rank decreases by 1... so on average you net 0 rank/lvl gains :(.. sob developer... it's one of those korean games where you can spend $100,000 dollars and STILL not reach end game gear! reaching level cap on 20+ characters is near impossible too)

Marvel Puzzle Quest, LOTR online, TERA, Star Trek online, Eve Online, Dragon's Nest... and more all quit for various reasons.

Only mmo I put on puase is Star Wars Old Republic, I do plan on at least playing through the story and forgetting everything else about the game.

Black on the PS2 - military FPS on a console, no more comment needed.

Policenauts by Hideo Kojima.

A bomb-disposal scene was too difficult...

I'm quite bad at RTS games and like you, if I would try a custom map in WCIII I'd end up with the same problem of not being able to defend the base while going for the enemy, but a much more enjoyable way to play WCIII as single-player is the campaign, or did you already finish that one? Overall, the single-player campaign is, besides more story driven and almost RPG-like, also much more doable. Just make sure to save often, to try out a different approach from a point things were still going well, as you'd often find out during play a better way to take on things.

I think I'm probably done with Unepic. Got to the final level and I'm just not having any fun trying to beat it. To be honest, I don't think the game as a whole is that great, but it was just sufficiently compelling for me to keep chipping away at it when I wanted to play something that isn't very deep. I think I might just watch a Youtube video of someone beating it to see the end and I'll move on to something else.

Like what? Looking for a good game to soak up time.


Dont Starve - Wanted to like this, just boring. Its not survival so much as time sink.

Sarced - Oiyee... horrible in every way. Purely a nostalgia game for people other than me.

Blood Bowl - Wanted to like this as well, huge WH40K fan and gamesworkshop in general for that matter, but minins for me. None of their games have translated well for me save Chaos Gate.

Outside GOG...
Heartstone - Got in the early beta and even paid some cash for cards. Wore off quick though, need a real Warcraft fix (preferably without Pandas).

Company of Heros 2 - None of the fun of the original. Interesting, no doubt. But something of a punisher without the fun.

Yeah, I´m a quitter. A rage one most of the times. I try a lot of games and in the end I keep playing the same games over and over. I´m more a love it or hate it game typo, and rather spend my time on the ones I love. Ok, so far this year (with only two months) I quitted:
Syder Arcade (too unforgiving)
Wake
Overcast - Walden and the Werewolf (boring, not scaring)
One Finger Death Punch (loved the game, but reached a point in campaing that turned almost impossible to progress playing on skill based, turning in a lucky mash button sequence for me)
Jazz (game keeps crashing, unplayable)
Inexistence (too much backtracking for annoying "find the key" quests)
Froggato (solid platform, but I think that I just don´t like them as in the past, got bored)
Jericho (in the middle ground for shooter and horror got nothing good from both themes)
CS:GO (jumped in for the nostalgia of playing CS 1.6 LAN with friends; no fun anymore of shooting and absent of friends, online community is a sad place...)
Mafia (is good to put you to sleep... seriously bad pace (second mission you spent 30 minutes working as a real taxi driver, really), crap shooting mechanic, not aged well, Godfather much better option)
Interstellar Marines (I did a try at the alpha, now I´m sure i won´t try the finished game, and good luck trying to put it to work now, many problems with unity engine)
Audiosurf (it´s ok for a time, but gets too repetitive, I prefer Symphony)
Tomb Raider Anniversary (good game and all, but rage quitted at final level, you must be too precise and right time to get the grips, I have no patience for too much try-your-luck grinding)
Darkout (too bland, no thrill to keep me)
Zigfrak (idem)
Greed Corp
Shufflepuck Cantina Deluxe

Phew!

Heading back to more thousand hours of STALKER and Civ IV...

I'm not quitting it but I feel the need to mention I'm turning to a walkthrough for the 2nd half of Heritage of Kings. It's not that it's hard, it's just so slow and uneven. A game like AOE or C&C I don't mind doing over and over to figure out my own mistakes but this one is just too big of a pain in the ass to do that with. Because my head is all screwed up I refuse to quit it but I'll be damned if I'm going to play levels over and over and over. Let me finish it and be gone with it.

Same for me. There's so much to like about this game, I keep telling myself I'll go back. But the strategy battles just aren't fun for me. I wish it had just been an action hack and slash.

Well, for turn based strategy, I'm mostly back on Civilization V again (the recent Sid Meier Humble Bundle got me the two expansions to it, and they change the game in interesting ways). Other than that I still fire Master of Orion 2 up every now and then.

That's a pity... I was looking forward to trying this out sometime with a couple of friends. Hope it doesn't bore me/us too quickly...

Borderlands: This I find one of the most overrated games ever made. It is extremely repetitive. I believe it uses the loot-addiction for attracting players but for me Borderlands is basically boring.

Games quit in recent years: Crash Bandicoot, Killzone, Borderlands, Oddworld: Abe's Oddysee

Sid Meier's Railroads! - I suck at laying tracks and it drives me crazy once the AI and I cross paths resulting in messy looking routes.

World of Tanks - Played the Panzer IV in closed beta , which was fun. Years after release, finally decided to revisit the game and grind for it again. Underpowered and no fun now. Not really interested in the other tanks.

Add Lord of the Rings: War in the North to my official list. I only played it for about an hour or so, so maybe I'm jumping to conclusions a bit, but it's not a Lord of the Rings game. All it was was hacking through enemies, and following a band that I really care nothing about. No lore, no ring, no fellowship. Well, it's uninstalled from my computer now, with no foreseeable (nor desirable) reinstallation in the future. While I'm not a huge LOTR fan, I was just really disappointed in this game since I was really looking forward to playing it since getting it in the Humble Bundle a few months back.

On a little bit of a lighter note, I also took Neverwinter off my computer last night. No real complaints, I just felt like I had gotten everything I could out of the game at the moment.