Magicka

Magicka has brilliant game mechanics - with one player, or with more - and a fantastic sense of humor. Basically, it's an amazing game. But it's held back by some unfair balancing (fast attacks that keep you stunned, one-hit kill moves from stupid yetis) and some remaining bugginess. I tried the Challenge mode with a buddy, and it was extremely fun, up until we kept falling through the ground.

It's a shame that Magicka isn't all that it could be, but it's still an incredible game that you really have to try.

Better than: Trine, Final Fantasy: Crystal Chronicles
Not as good as: it could be, unfortunately
Also a better fantasy/sci-fi parody than Overlord: and a better video game canon parody than Eat Lead

Progress: Finished Adventure with 2 players, found all the secrets