thank you for playing! you hit on many good ideas that I would like to implement.
I like the wording of "low-to-no-risk levels" at the beginning. Unfortunately, the tutorial barely got finished within time as it was, but the tutorial levels in the game are just like any other level, so it should be straightforward to reorder them.
thank you for the report on "if humans are already in the clear zone, and then the last remaining human dies, the level doesn't clear." this is because the level clear zone checks for level clear when a human enters the clear zone, an enemy exits the clear zone, or a human becomes infected. I need to add a check for when a human dies to out-of-bounds as well.
I think a total human counter is an excellent idea! this will only become more important as the levels get bigger and more complex.
finally, thank you for the kind words! I put a lot of effort into making the UI pleasant to use with sound fx, so I am glad you enjoyed it :)