I would have to say Battlefield 2...
Temple of elemental evil. Didn't do so great with scoring full of bugs. But a mod came out and made it very fun. Remember buying it and playing it not getting very far years later I downloaded the mod and finished it.
Pool of raidence ruins of Mythdranor. Claimed it used third generation rules but it was 2.5 rule set lol. also had a bug when you uninstalled it it would delete a windows file. But I really loved it. My first proper rpg game.
Starship Troopers from 2005 (the fps)
man so many problems in that game. and yet strangely fun
Play games, not platforms
The Walking Dead FPS. Yes, I know, you can throw me with rotten fruit and veg now.
I really enjoyed Alpha Protocol even though it had an unfavourable reception for being buggy and unpolished. I didn't play it at release so they might have ironed out a few of the bugs by then but I enjoyed the whole secret agent theme and the fact that your decisions had significant consequences, impacting who would be your ally and who would be your enemies. I even remember feeling a bit remorseful for making a selfish decision on one of the missions.
The gameplay could be frustrating, especially if taking the stealth approach. And the game made the same mistake with the bosses as Deus Ex Human Revolution, BEFORE DR:HR did. Despite this, the story line had some interesting twists and a few interesting characters and the gameplay had some good moments. Overall I enjoyed the 20+ hours I sunk into it.
Bulletstorm...fun and crap at the same time....what fun
Test Driver Unlimited 1 and 2: To be fair they both got mediocre scores from critics, but I really enjoyed the fact that these games gave you over 1000km of open road to explore, and a whole host of awesome cars to drive. Yes it was buggy and yes the races were not very varied, but I still spent hours just driving around the country side buying houses.