Well, it's a test, but it looks promising. The attack sequence if you just stay on the ground and keep pressing 'C' looks especially great.
The 'X' special doesn't seem to do anything yet and there's no roof, so perhaps the particular version 0.04 isn't uploaded yet.
Anyway, I think instead of adding a roof, it might be better to add a cap on the upwards force you apply to the punching bag since you'll likely run into a similar problem once this becomes a full-fledged game. And then, even if the enemy is blocked by a roof, it doesn't look good if you can propel him across the whole screen.
A couple of times I ran into a jumping bug in which you would fall to the ground more slowly than usual after a jump – this is hard to reliably replicate because it doesn't happen every time, but I think it has something to do with with the jump attacks. The gravity or whatnot is lowered during the air kick but it isn't always reset to default correctly and all following regular jumps use the lower gravity until you perform another uppercut or air kick.
I'd add an attack to do while walking since now it's either standing still or the two jump attacks; nothing if you move around on the ground.