As alot of people have commented - pressing E to pick up is unnecessary. The game feel would be better if it was instantly.
I don't see where the game fits the theme? You pick up fishscales .. I think it vaguely fits the theme. I think if the character you play scaled (either becoming bigger or faster, idk) - then that would add more to the theme.
The gameplay was fun but it become repetitive fairly quickly. I would create a smaller map, with maximum 3 treasures. Also nice effects for when you don't meet the quota! :)