Not bad, but lacks originality.
Aside from the fact that it is a very simple avoid game, there's a few problems.
The speed increases too drastically, and the slow down cells really don't do enough to help you, a couple of seconds of slowed time then back to normal just doesn't do it for me.
The graphics are very plain, but that kind of works - maybe some slightly different shapes for the viruses would make them easier to discern and therefore easier to catch.
The high score system is nice - easy way to add replayability, but the game itself is lacking slightly too much for it to really work to its full potential.