Nice game and fun to play except when you upgrade twice your strength then you one shot every single enemy. It could have been a great idea to lvl up the enemy every time you open a new gate.
And for the ending it would have been nice to have a button to quit game or close the menu instead of having to force the app to close :')
I'm pretty sure that it could be a nice game to play if you implement more levels and each time the enemies gets stronger :)