A funny design, a curious idea, but it was difficult to remember the rule about the directions of attacks. I think it would be cool to hide a hint about the direction in silhouettes of sprites.
Also, I was initially confused by the long (albeit cool) animation of the disappearance of enemies, not synchronized with the last delivered strike (In the sense that the delay in the death animation seemed excessive to me).
In general, this is a pretty good game, which makes you think about the next move and the changed controls.