This looks incredible! Phenomenal artwork and sprite animation! Pretty brutal gameplay to start off with, but the difficulty level is not a turn-off.
Crouch feels like it's missing. I know it's not referred to or implied anywhere, I just found myself trying to crouch the entire time I was playing.
Some of the obstacles (spikes) felt a tad out of place on the stairs. Not unfair or anything like that, but they just visually didn't "fit" to me."
Aside from that, this feels well polished. Can't wait to see (and buy) the full release!