Very well made and polished game. I can tell a lot care went into it. Love the detailed tutorial and transitions ( not enough people make scene transitions ;) ) and how responsive the buttons are with sounds, higlight when hovered.
The concept is quite original and could be expanded upon for a big puzzle game with many mechanics.
Graphics are also very well made in a cohesive and charming style.
The % chance of beating a level is rather weird though. It means someone can repeat a level after getting just one virus and eventually beat it. I think it would be better to just have a minimum amount of viruses you need to get and the "goal" number to perfect the level. That way people who aren't as good can still progress and the challenge is still there.