Here is a teaser trailer of Frozen Bytes sequel to a particurily fun side scrolling platformer using the source engine. If you have not played Trine yet you should, its a great example of how an indie game developer can turn out a game to rival the big boys. It’s basicly a 3 character platform game where you swap between Knight, Wizard & Theif characters to take advantage of their individual skills to overcome puzzles, defeat enemies and find treasure. If you ever played The Lost Vikings a game from yesteryear its pretty much like that. The original never featured co-op play on the pc but from what I have read the sequel definately will.