(This is mostly my personal opinion, so don't take too much stock in this)
Bearing in mind the game costs 864 Yen / £5.00 / $7.30 I'd say it was pretty good. It was a bit of a challenge avoiding those hitboxes; and considering the camera moved with the character I couldn't see what I was jumping into sometimes, adding to the difficulty.
Cleared it in an hour. I was a bit disappointed that there were only five game over scenes. Maybe it's because I expected a bit more guro or disturbing scenes since the environment reminded me of Splatter School/Beach from Ankoku-Marimo's stuff.
Overall I'd give a good 7.5/10 and I hope to see more from the creator.