I thought that this was a fun little platformer. I really do like the low-res pixel art style. It's one of my favorite art styles.
However, the tiles do have this glitch where black lines appear frequently. I actually ran across this problem for my major indie game I am currently developing. When you make a tileset, you should make your tile textures one pixel bigger in each direction and duplicate the edges of the tiles out, if that makes sense. They would clip to the second edge,instead of clipping to nothing, which makes it less noticeable, if at all.
Other then that, and the kinda slow attack animation, I liked the game