Strategy and bugs
The only thing I would suggest is to allow us to skip the tutorial without missing out on the 1000 coins. And to allow us to spend them before playing the 1st stage too, because if I don't beat the first stage in -2 seconds, might as well restart the game. I find the best thing to invest in at first is speed, but I haven't broken 700k yet. Perhaps you could post tips on how to spend.
Two possible bugs. You click once to start the clock, and once to spread the virus. If you double click too fast, it's like a dud and no virus shoots out. Also, when you click the "X" on notices, a bomb gets used.