This is awesome entry, graphics are great, and sound/music maybe even better. I've locked myself once on a bat, see in the picture. I had to wait for bat to move.
Maybe the only suggestion on the graphics: all animation are smooth as heck, but attack for some reason is not. Hm.
I'll give this game another try because I've locked myself I think, same place as Redz. I think you get a powerup there, a pistol or something? Well I did not get it, because I opened the chest, immediately threw a bomb by accident and got nothing I believe.
Many guys shooting from the holes were not shooting for some reason. And I think there are just a bit too many guys only waiting to be stabbed looking the other way;)
About slippery, multiple people already told this. I think its not a great idea to use a physics to move a character, and that's the problem I think. Platformers usually work better with good old arcadey, handwritten physics.
Anyway good job! I'll finish the game later.