Hard and short, but entertaining
I thought that the bullets were too small compared to the size of the enemies, it was hard to hit everything...
The swinging motion Neru uses means that she can swing past you and ram you from the side, but that's actually part of the challenge.
There is a score board to keep track of how well you've done after you finished which was a bit disappointing. I was surprised that after the 20 seconds had passed it just restarts. No winning animation? (Or even some kind of boss?)