Good game, but a few problems I had...
I first built my size to max. After that the game is a complete breeze up to the last level. If you sit on top of the virus it is actually impossible for the "enemies" to reach the center. You can sit there for a minute or two and build up enough cash to buy everything in the game. Health respawning shortly after every use makes it a little too easy later on. The last level or two the game begins being challenging again, but if you set a mine on top of the virus you get a second or two of an "unreachable" virus in order to sweep out and grab white blood cells and health. All this is really gameplay issues that I personally don't agree with but don't truly detract from the game. The only REAL issue the game has that I saw is that enemies would do damaged BEFORE disappearing into the virus and this caused some to be able to do double damage if knocked out of the way at an unfortunate time. Of course using the strategy listed above, the point becomes moot. For a sequal I would personally suggest a larger "entrance" for the virus or a smaller range for your cell, a longer respawn time on health, MOWR upgrades, and possibly a more fitting ending, as destroying all viruses would cause the extinction of virtually all life on earth. I was kind of disappointed that I didn't see that pop up after you receive your certificate of awesomeness. Or atleast some humorous result of your actions. That is just personal taste once again though. Really good game for a solo project.