------------Spoiler for GTA IV----------
The last mission where I assume you kill Dmitri is so loving buggy/not well done. I've tried it multiple times, just today twice not being able to loving finish it. You get in the boat, and immediately a missile hit near me, flipped the boat, and that was game over. Then I got to the part where Jacob picks you up out of the boat into his helicopter, I got like 10m away from the bottom and he flew it unrealistically fast upward and over land.
This wouldn't be an issue if it didn't start you over to the initial assault on the casino every time you screwed up.
Otherwise, I love this game, and I wish I could finish it.