Honestly 5/5 on the theme. That is such a cool mechanic, and its so fun to come up with wild strategies for the game when mutating your animals. the one problem with the gameplay is that... while its fun to come up with minions soon enough I just start putting in random mixes of animal because it takes too long to strategize what options are the best for your army. this happens around the time where you unlock more animals. maybe reduce the animal count with each wave. but anyways.
Its really cool that a family made this game.