If I knew I was going to die, I would probably play a quick game of Tetris to get it over with. I couldn't possibly enjoy playing any game if I knew I was about to die.

But for the purposes of a question like "if you could only play one more game for the rest of your life", it would probably be some sort of MMO, or a roguelike with lots of replay value. World of Warcraft, FFXIV, or Enter the Gungeon.