Thanks for the review!
The game is indeed too easy in the later levels but worry not, we are already working on a new version of the game with many more ideas.
The art and sound is a valid point, we both are not skilled in those department, so for now it will just be bought or free assets.
PS: Did you perhaps forget to save your rating?
I see we are still on the same number as a couple of days ago and would hate not to get a rating from someone as positive of the game as you :D