This is probably more of a coincidence or an unintentional influence than anything else, and there's always the possibility that we're imagining things, but doesn't Ontama's protagonist Beat look somewhat familiar? He looks like a cross between Sonic Adventure-era Sonic (look at the poses!) and Jet Set Radio's main character, also named Beat. Well, if you had to pick two games to resemble, you could do a lot worse than these, both of which had fantastic art.
The actual game, a rhythm-puzzle thing that we totally want, doesn't look like anything else. We've got new screens after the break.