Very creative for an immunity tower defence. I enjoyed the music and the sound fx a lot. the two things I would comment on are:
1- make the money automatically go to your bank or make a simple mouse hover collect them because the speed at which I clicked as fast as I could never matched with their despawning speed which sort of rendered the point of killing the viruses pointless (why buy more when I cant pick up enough coin fast enough to compensate for my investment you know?
2-I also agree that yellow should be introduced in later levels, but given as a few slipped by ... but i didnt get a game over it doesnt seem consequential to keep them in HOWEVER i think their capsules should be worth more due to their speed.
Otherwise very fun game :) I enjoyed it a lot. Congrats on the submission !!