I know that Sanrio (especially Badtz Maru) is pretty popular these days in the hardcore scene, but I really like it. In fact I have been down for Sanrio since day one.
Anyways, if you've played the disappointing Sanrio games for NES (Sanrio Carnival and the other, marginally better one that I can't remember), forget about them. SSB is really, really fun. It's more or less like a combination of air hockey and soccer. The object is to kick the ball into your opponent's goal. The first stage, on the left, is pretty straightforward, but as you advance, the game gets pretty tricky, because there are pinball-style bumpers, fans, and other obstacles that redirect the ball.
There's some kind of "super kick" thing you can do where you build up strength and then release the button and kick the ball super hard, but I can't figure it out. Another kind of neat thing is if you look, in front of the goals there are little blocks. When you break the blocks, it releases a power-up sometimes, which kind of evens it outa little more.
I think it's a little obnoxious how girls who are like 20 years old think it's cute to have a Keroppi lunchbox or something at a show. Sure, it's funny for a little bit, but it quickly gets old when people *try* to be cute. To me the best part about Sanrio stuff is how Japanese it is- for instance if you look at Sanrio.com, and go to the Characters page, they have really funny descriptions. Like it says for Badtz Maru "He rolls his eyes at the humorous life in Gorgeoustown."
Well I guess that's about all I have to say about this game, it's pretty simple- but also really fun. I have only seen this ROM once, so good luck finding it. I suppose if you *really* want it I could probably work something out for you- since I know how desparate you Sanrio types are. A new trinket is like crack to a Sanrio fan. Here are some more screenshots for you.