Well, even after quite a while, online multiplayer for Castle Crashers still seems to be completely screwed, as I have yet to connect reliably to even a game of All You Can Quaff. However, it is a testament to the quality and general fun factor of this game that I still find myself playing it every time a few of my friends come over.
I've taken two characters (Fire and Lightning) through the end boss, collected every animal, beaten all the arenas but Icy, and collected most of the weapons, although the Chainsaw still eludes me. Part of the game's long lasting appeal, for me at least, is the multiplayer. All three friends and I need to do is say "Hey, we've got two hours to kill, lets all start new characters and see how far we can get" to set it off. Having four of us grouped around a TV yelling encouragement (and occasionally insults) at each other is a great experience, and the inevitable fights between us over the princess almost always end in hilarity. It's a great game.
I loved Dan Paladin's art style in Alien Hominid, and I love it more in Castle Crashers. It's just more proof that a game doesn't need to be normal-mapped and anti-aliased out the rear end to be fun and entertaining. Throw in the hugely enjoyable soundtrack and addictive gameplay, and you would have a work of genius on your hands. Or so you would think.
My main beef with this game is that the gameplay is actually propped up by the enjoyment factor of playing with your buddies. One of my friends commented on our last playing sesh, "you know, if this was only a single player game, it would get really repetitive really fast." When we all heard it, we had to agree. The combo system is fun for a while, but once you level up there's really no need to use anything but XXXYY with the occasional magic attack thrown in to decimate pretty much any enemy you come across. The bosses are varied and entertaining, and require different tactics, but running them again and again can get old, especially since they dont seem to scale down enough in difficulty to accomodate single players (the Conehead Groom is the biggest issue I can think of, as his spin attack has the potential to take you from full to dead without time to chug a potion).
All in all though, this is a fantastic multiplayer experience. Once they fix the online issues (we hope they will eventually), people around the world should be able to connect and enjoy this game with one another - although in my mind, it won't replace the pure throwback joy of four players crowded around a single TV, yelling abuse and praise as they castle crash their way to glory.