Great game! I'm gonna go back to playing right after this post. Some improvements could be: have the ninja lunge towards the entire cursor instead of exactly where the pointer clicks, enemy variety (Either different types like a spiked ball and chain, or elite versions of existing enemies, an archer who jumps back or shoots two bolts instead of one), kill counter, a pause screen where we can't see plan our next move. Sometimes the lunging distance seems to change too so maybe a transparent distance indicator might be cool too :)
Really cool concept. I found a small glitch in level 3. When I walked close to the edge of the map, the dropping enemies missed the playing field. I would have taken the free kills if the game didn't freeze once I defeated everyone else.