Nice try!
It was a good shot. It had simple sprite work and simple backgrounds with simple land. I think it could use a little work on a few button responses. I think, as with most platformers, that depending on how long you hold down the space bar, the higher the character will go. Also, there's a bug where there's this part in the beginning where there's a tunnel. I just jump up from the right and Mario gets stuck down there, so... there's nothin' else to really do. XD All in all, it's a fun concept, it just needs some fixin' up. ^_^
~Dylan ^_^