The level design here is really nice, with a great variety as well! I liked how you designed the UI/UX, allowing the player to first view the entire room from above, then choosing which human to infect. I especially like the mask mechanic, where you must first remove the mask before infecting them. This means only hitting some humans once so that you can infect them later, forcing you to think ahead which I love.
I think it would've been nice if infected humans could walk through doors once another human opens it (but doesn't close it yet), because, well, the door's open! Also, having to wait around before infecting someone is a bit tedious. Maybe this could be adjusted by allowing the player to "fast-forward" the game? Or designing the levels in a way where the player doesn't have to wait too long.
Otherwise, this is a really great submission with a slew of levels! Great job!