I decided to have some fun with Quake IV since I wasn't sure what to play.
And so the game ends as well xD. I marathon ed today, and I enjoyed myself as well, though the game is actually quite short. It took longer than what I expected, but playing on General, you tend to die a lot. Also forgetting to save, and at times getting lost can also have an effect on how long it takes to complete the game.
Steam shows it took six hours... though I was aiming for four.
Great, game, and I will be playing this game again some time in the future.