Not that bad
Collision detection could use a bit of work, add some sound effects to things too perhaps. I know it takes away from the awesome music however it makes the game more interactive. As this is a plat former of sorts. I suggest you maybe add some more baddies... ones that you don't just lololololroflstomp. Just my input though. Maybe give the dude a gun... kinda Megaman-esque... inside a robot dinosaur...