I Liked the game enough to finish it but...
Here's a few problems i had with it. The warp animation comes too late after the warp making timing annoying; the idea of the bad guys you can't hurt(without the powerup) just having spikes on their heads seems like a cop out to me like you said "bad guys...bad guys what can i come up with? Oh, I know i'll take the normal bad guy and put the only other real obstacle in the game on his head"; the death animation is cute but takes too long for my taste, on level 28 I died so many times I got frustrated and the seconds it took made me switch to just pressing the "r" button over and over again; speaking of level 28 the difficulty curve of the game made no sense, it felt like 27 levels of getting familiar with no real challenge and then BAM ridiculous and back to easy; the spikes hurt you if you jump up next to them and over which is illogical and annoying but i know thats how it usually goes; the one block gaps can just be walked over; the last thing i wanted to say may just be me being stupid but I had no idea what the orange guy in the bonus stage did.
I had no problem with the background and the character being the same colour like the other reviewer said, I loved the art style and the music fit the game.
As for the baddies being white and you as part of this dark environment, does this indicate any kind of player as the bad guy scenario or was it just a aesthetic choice? I Love it either way. The power ups were well handled and the animations for them brilliant. Keep up the good work, I Look forward to it.