It is a rare event when my wife says that I really ought to blog about a flash game.
The gameplay in Viricide is pretty standard: shoot the enemies that come on-screen, collect bits to buy upgrades. You get more toys and a better ship over time, while the enemies get more diverse. Good, and you have probably played something similar before.
The level introductions are what sell it. You are killing bugs in a computer. You fix its systems, and it talks to you. The humor starts with displays of the problems you are fixing, such as excessive enthusiasm or explaining the obvious. It visits a less friendly computer. You then go into the background story, which could be successful or not; I expect that people rejecting the emotional manipulation will find another layer of humor in it.