Trine

Imagine The Lost Vikings set in medieval swords-and-sorcery land. You have a wizard who can float things around, and magically conjure up blocks; a thief who can swing from a grappling hook; and a warrior who blocks falling rocks and beats up skeletons. Oh, also, there's co-op - you switch between the characters in solo play, or multiple players can use each character simultaneously, making for wicked-fun physics-based hijinks.

As a single-player outing, Trine is interesting and inventive, if frustratingly difficult. Dying seems too easy, especially with all these spikes everywhere. Multiplayer is fun not just for the teamwork-oriented challenge, but also because you can screw around and toss your friends into fire. The physics-based game world is definitely engaging, and I'd love to play around with it some more.

Problem: co-op is local only; there is no online play. How lame is that? I'll gladly buy the game at full price if this is added in, but in lieu of that I'm waiting for a price drop.

Progress: Played the PC demo solo (didn't finish) and co-op (AWESOME)