I took the plunge and bought Castle Crashers. I played Alien Hominid HD, but I'm happy to see that this game has better music and an easier difficulty. I'm yet to play it in multiplayer, so feel free to invite me.
I'm playing as Alien Hominid, who is unlocked for those who own the game (though I had to play Alien Hominid HD and update it for Castle Crashers to recognize it):

I'll need to download the Castle Crashers trial.

Damn,I really have high hopes for this game and whenever I get a little extra change I'll pick this one up and probably buy Alien Hominid just to get the character.