just couple ideas if you guys elaborate on this.. some wondering monsters in the forest would be fun to avoid. maybe when the main character actors are in danger the player can use stealth to avoid them. maybe player actor turns into a tree (which it sort of looks like). yeah the metal gear solid mechanic would work great ; ) maybe some of the wondering creatures could offer clues to help you find your friend or maybe some of them mislead and make you wonder into danger. would be cool if you could also look for foot prints to track down your friend. or if you have a level without snow then maybe player could use found objects to leave visual cues to the other player, etc.. and of course some kind of narrative to drive the relationship of the 2 main actors. would be interesting to utilize sound as a method of location as well. maybe one of the actors can whistle and the other player can hear what direction the sound is coming from.