Great fun!
Loved the look, and really appreciated the fact that everything from your movement down to the credits scroll stuck to the 8x8 pixel grid. I actually made the controls a bit jumpy but that was no big deal once I got used to it.
Difficulty seemed punishing at first, but for each level, after a few tries I figured out what my strategy should be and was able to clear it soon enough. Also by the end I'd gotten good enough that I was able to beat the final level (which was a really fun surprise btw) on my 2nd try.
My only knock would be that the spikes didn't stand out quite as much as I needed them too. More than once, I walked right into one because my brain had tuned it out as being just a background item. Not sure the best fix for this, could be recolor or fill in the spikes so they look more prominent on screen, or maybe give them a small animation. Or maybe I should just have my eyes checked! ;)