GoNintendo has a video on their site from Japan/Korea/China (I can't read characters) about some of the NES's big names going against Mario. They all try the first stage and man my favorite character ever couldn't even jump over a pipe. The other funny part was at the end where, I can't even explain it.
This other video is Mario on the Atari. This is as 2D as it gets but there is one problem, the one problem that when the video was over I knew it was fake. The music. There is no way an Atari can play that music. It is still cool looking.