My first instinct is a big resounding Nooooooooooooo. Now, if you actually mean a sort of mental mystery instead of an actual puzzle, perhaps (like in trying to find out history you have to piece together the clues you get. But if you're meaning actual physical puzzles - absolutely not. This is an FPS, and this is an action game. I don't want to have to light torch A, and then run down a hallway, jump a crack, and light torch B in 5 seconds. that kind of gameplay should remain out of an FPS. This isn't a platformer or a puzzle game. I don't want to have Zelda style dungeons. It would absolutely ruin the game game for me.