I was trying to play a one-monster game (at least for the beginning part) but it turns out that you can’t put your last monster in the zoo, and as soon as you summon a second monster, enemy groups permanently have two. Which means that right now you can’t do a one-monster challenge with anyone except the five starting monsters.
My preferred solution to this would be to have the number of enemies depend on the number of monsters you currently have in your party, but I understand that that would be a balance change you might not want to do.
Other possibilities include:
– Allowing you to put your last monster in the zoo (would probably require adding some more checks to make sure you don’t go through the portal with no monsters, etc.)
– Only updating the “maximum number of monsters you’ve ever had” counter when you go through a portal (or start a fight, or whatever).