I like the idea needs more balancing. Hard didn't seem possible but seemed really interesting, liked trying to pick the right upgrade and balancing greed on XP vs killing rats.
Normal was too easy, didn't try easiest difficulty.
Love the little touches of the purrs, the eyes following the mouse and cats having sweetspots. Could be funny to have each cat have a different zones they want petted or not.
Also it seemed the music failed to loop.