Definitely needs some sideqests, bosses should have less HP, different weapons should actually be useful for different strategies (other than puzzles), and WHO THE HELL USES COLLISION DAMAGE NOWADAYS?!
This could be a good start, but you should label it as what it is: a demo, a test (I mean in the title). Maybe even make a little goal right now.
I would play the complete version. Just a little suggestion: allow us to deselect blocks and make the critter a bit more agile.
Craptastic game when you really can't win. I mean, other games have the RNG cause you to have sure failures, but at least in those there are soem ways to make up for that (extra lives).
Congratulations, this is the crappiest non-joke platformer I've ever played. Controls are broken, challenge is based on stupid jumps and there is no real feel of fun.