Not bad- I'd think that a game, where you can dismantle a floor could result in player getting blocked... and it did, but then I ran out of time, restarted the level, and readjusted my tactics.
The graphics are ok- You clearly have your style, but some more details could give it more character.
The gameplay! I liked the concept a lot (picking up floor, and enemies, even cannons was really fun), but it needs a bit of polish. The jump was a bit floaty, and I swear, that the jump height was sometimes stronger, and sometimes weaker! And I couldn't beat the boss. I couldn't reach him, and he only jumped around the platforms.
Over all- great idea, that could have been even better with some polish. Nice!