Cool setting for a game. The gameplay was quite nice, although I feel there wasn't enough feedback for hitting a boss as well as taking damage as the player.
The backgrounds are very nice looking. The boss designs are interesting. I like the mix-up of attacks with punching and kicking, although I wasn't too sure what the exact difference was and just spammed them both.
The green boss with the volcano background was able to pin me in a corner. I feel that the player should be able to pass through bosses on a platformer like this. In other games of a similar nature that I've played, they've also done it where you can pass through a boss but you take damage and knockback; although, that's obviously a lot more work.
The whole swapping weapons things is a very cool theme idea. I didn't really understand how to use the weapons though; sometimes they'd work, sometimes they wouldn't. Also, I feel that there were too many attack options: punching, kicking, throw, and special. However, for a larger scale game this may work as you could introduce them one or two at a time.
The SFX were a bit lacking but the music was nice it set a good atmosphere.
Overall, a good entry.