My game mechanic is kinda similar to yours in the sense that you have to scale a square, but you kill enemies with it. Yours is definitely better tho :P
I had fun! It didn't really connect for me why i could continue without completing the challanges but it made sense at the end with that cool animation
I think the ocean getting repopulated is cute. I had some fun trying to destroy the boats, although for the big one it was kind of tedious and I expected something to happen. I also liked the shake when destroying the boats