Sorry to hear about your frustration! Every prefab room should allow you to kick every Jack o' Lantern, but maybe I made them a bit too tricky. You can trick the frogs into eating the kobolds but it's easier said than done.
I'm gonna release a gameplay/content update shortly that will add selectable difficulty. It'll tune a number of things like enemy aggressiveness and make the penalty for getting eaten less harsh on the lower difficulties.