Overall, this is quite good. Nah but seriously, this shows a lot of promise! I enjoyed the implementation of the axe throwing mechanic and how the level design makes use of it. The music and sprites are also very well crafted and I'm excited to hear/see more.
My main critique is definitely the camera. It is perfectly fine on the horizontal axis, but a bit slow on the vertical axis. There were times where I couldn't see what was below me and had to wait a while for the camera to catch up to me before I could proceed. It's not a huge problem, but one that I'd like to see amended in the full version.
That's really the only issue I have in an otherwise very well made platformer that I can't wait to play more of. Great work!