Sick, with issues.
First off, great job, I like the Mario-esque vibe of it, and the 8-bit music and sfx are awesome but you have to address a few issues before it goes gold.
For one, for a first level, the jumps are way too hard. You want to ease the player into the control scheme and balance challenge with advancement. I have no idea how long a game you want to do here, but if I'm having trouble making past the first stage, I may be inclined to skip the others.
Second, your hit detection with the breakable blocks is way off. They are smashing when I merely wish to use them as a platform. I also experienced this falling THROUGH them.
Lastly, zoom it in a bit. You have pretty good detail on the sprites and could afford a to increase the magnification, it would give it more of an authentic 8-bit vibe.
If this is a beta, and you can iron out some of the little glitches, you could have yourself some featured material here.