Cool game! I think I've heard about these mechanics in a Sam Hogan video, but without the cure, which is a nice twist, and ends up leaving good possibilities for levels. The interface showing which ones will die and where they will contaminate is awesome, made the experience so much better. Also, that's a lot of levels! I spent from 5pm to 10am making levels and still only got to make 20. One small critique, the volume on the contaminants' death sound is way too high when many die at the same time, and since you're using Godot as well I'm just gonna give easy instructions for it: next time you could channel the SFX through an audio bus and put a hard limiter effect on it. That makes it so the volume won't exceed the DB volume you set on it no matter how many sounds play at the same time. Still, really good game and really enjoyable. Congratulations!