Thanks for playing!
We had to cut a bunch of things in order to make the Jam deadline. But I agree, more Rock, Paper, scissors, Lizard, Spock, etc... elements would be neat to implement. Also had plans for Rats, and a Boss fight, but ran out of time.
The Combos would heal the Nightmare Damage meter when you would hit a set length of combo. We want to expand on the combo system in a future update.