Well I have only 32bit PC so I couldn't play it. But I try my best to rate it by the screenshots!
The visuals are quite impressive and look cool but I think the leveldesign looks a bit to similar. You could add a bit varation to the background for example with a stone pattern or other things.
But thats complaining at the highest level!
I can't comment on the music, game design, ... but I know that making a platformer is really hard so you can be really glad to finished it (bzw. the prototype). Well done guys! :)