Cool! reminds me of lemmings. The spawn and lock system is clever, though the little guys can be frustrating to control (i keep bouncing off the ceiling when trying to jump over frozen mongats in 2 tall hallways, frozen mongats are still very round and very easy to slip off of, jump height feels inconsistent) I wish i could spawn mongats where my current guy was so i didn't have to roll them through the whole level over again when i needed a new mongat.
All in all really clever! i like your execution a lot good job c: