Battle Stadium D.O.N. is a fighting game like
Super Smash Bros. Melee only that I think it's even more fun. If you're an anime fan than this is pretty much a wet dream

D.O.N. stands for
Dragon Ball.
One Piece.
Naruto. and features 20 characters from all these franchises.
The big difference from
Super Smash Bros. Melee is that you're not trying to throw your opponent off the screen but rather go for a K.O. Another difference is that all characters (up to 4) share one lifebar. Everyone starts with the same portion of this lifebar. If you hit your opponent he will lose energy in the form of red balls (in different sizes depending on how hard you hit him). If you collect these balls you get the energy that your opponent lost. However, if you're playing with four friends it's more than likely that someone else will steal them which makes for heaps of fun, some serious chaos and a lot of cursing

In order to win all your opponents have to be K.O. at the same time, which means if you have no energy left you can still fight and gain some energy back until there's just one character left standing. It's pretty easy to pick up and it's not like other fighting games where you get owned badly by experienced players.
The focus is defenitely on multiplayer sessions. For single player you have a mission/arcade mode in 4 difficulties. You have to master some challenges (like jump 50 times in a match or beat your opponent in 60 sec.) to earn coins which you can use to earn new characters or arenas. The missions requirements are in Japanese so it won't hurt that you can understand that

There are FAQs on GameFAQs or other places with translations, but the mission requirements just show very briefly and you can't read them in the pause menu so it's a bit tricky but it's possible.
All in all it's a very enjoyable game, in multiplayer more than singleplayer. I like it a lot and I'm not even a big fan of the animes. If you like these I'm sure it will add to the fun even more.
Below there's a link to a video with a typical match
http://www.youtube.com/watch?v=eTfRjciJEVYI hope I could answer everything you might wanted to know about the game
