Edit: From what I can gather, it's the usual side-scrolling beta-em-up affair, with a multiplayer fight mode added. Ad-hoc though by the looks of things, no WiFi (I doubt it'd really work for a fighting game anyway).
I just gave it a quick go and the first part reminds me of Super Smash Bros.
There were 3 of us and we had to beat down a boss. I'm not a fan of Naruto so I don't know the names and stuff.