This game is a great single player experience, but it's best played with a friend in co-op mode. Granted I haven't played through the entire game yet I don't know for sure but I can pretty much tell that in later levels you will need a cooperative partner unless you like dying a lot. There are plenty of collectibles in this game if you like collecting as much as I do. Collectibles are in the forms of Weapons, Health increases, Ammo increases, and more. Puzzle elements in the game are fairly simple early on but progress fairly quickly in terms of difficulty as you play further into the game. Overall this game isn't worth the full 1200 MSP asking price, but is worth grabbing when it's on sale for 800 or 600 MSP (I bought it when it was on sale for 600.) Just remember to bring a friend if you want to get your full value out of this game!