Nice little game, fits the theme and our current world situation very well.

If you tweak it a little bit it could be really fun, movement and shooting have already been mentioned, but maybe making the world smaller and not deactivating movement on healed people would make it more challenging. Limited masks or maybe just a reload timer would give infected a better chance to give you a hard time :D

Congrats on the submission!

Moving faster than masks and could use a counter of infected.

Also movement. 

Besides those good base.