Such a clever idea for this theme! These quick time events are very popular. Some feedback...

- I wish it got harder. Once getting into a rhythm I found myself able to constantly beat it and not challenged. This could just be that it gets a little faster and more tentacles. From all sides would be good

- The map you've created is really beautiful, but ends so suddenly. I like the idea of a square, but maybe use fog or other means to kinda soften the blend. Could break away some voxels into the distance.

- If you wanted to continue work on this, I could see multiple levels and themes.
 

- AJ