The game's concept is pretty cool!
I played this in single player mode, and like other comments mention, I found myself standing still most of the time (the difficulty took way too long to ramp up). I felt I didn't have much to do, except dodge the incoming soap. When I started the game, I thought I would get scored on how many other germs I could save, but apparently, they were just there as decoration. It'd be really cool if you had abilities/powerups to herd them around and save them!
I feel that with some changes, this game could become really fun. Cheers!