I really like this game but it's just so hard that I can barely get to a point where I can buy things from the shop.
-The first time you can access the shop it seems to be impossible to have enough money to buy anything, I used it as a chance to catch my breath which was also nice but maybe a cheap item you could buy would be a good addition?
-I might be bad at the game but I lost a life almost every single time the two colours I needed were on opposite corners, I do think some extra time (just a little bit) would be nice. The extra time could be active just for the first few levels/fights so you can keep the challenge of the current game.
-Art and UI were great :)