Wow, very well thought through game and great amount of polish! Everything works well, from game mechanics to SFX , audio ,animation and upgrade systems . Very well done! Plus cat characters, bonus points for that!
One thing I would add is maybe a pause screen during gameplay , small thing ,but lets you stop the game ,just in case. Maybe allowing the player to skip the scene after you lose would be nice as well.
All in all, reaaaally well done on this one ! You got my vote!