Super smash bros? with like.. link, pokemon, metroid, and all the nintendo characters.
What I think you should do is make it look.. uh less fake and try to make the enviorment more realistic.
Mario Bros. was like, before Super Mario Bros., much less SSM. It was a single screen game where enemies (koopas and such) came out of warp pipes on either side of the screen and it was your duty as Mario/Luigi to dispatch of the sewer beasts ASAP.
Also, a realistic style would hardly be fitting. That would mess with the charm of this thang. This is one instance where when the person says "That's the style," that's the style.
I like the tiles (for the most part) so far. But what's with the division line in the platforms? Looks wacky. And unless your BG is going to be black, I don't think that having the grass fade to black would make much sense. I hope you're going to add as much detail to those bushes as you did to the rest of the bg? But first, make them match the perspective of the platforms, or at least make them vertically offset a bit. If they're tufts of grass, then they look :/, so you might wanna work on that a bit.
The character looks odd. I'm not sure what it is, though.
I really like the dirt just above the water though.