I think my biggest disappointment with castle crashers is that it didn't jump start a new golden age of beat'em ups. the game is great, just no devs dared release anything else like it at the time.
The Scott Pilgrim beat'em up which came YEARS ater was absolutely excellent...except for the fact that at launch, and then for like...two entire years, it didn't have online multiplayer. Yeah, it had couch co-op, as all beat'em ups should, but not having online multi in the era it came out really made the game DOA for me. I beat the game once and that was it.
Is the new turtles game on steam?