I really like the graphics and the music and the general feel of the game. It all worked really well together and provided a cool atmoshpere. I did find a few areas that I think can be improved:
One of the main ideas in the game, which I thought was really cool, was the virus meter and staying inside of the bubbles. I quickly found that this entire game mechanic is nullified by the fact that the meter fills up way too slowly and goes back down way too fast when inside a bubble. This allows the player to spend a long period of time outside the bubbles without any consequences, I pretty much ignored the fact that this game mechanic was even there. Since the bubbles are so large and there are so many on the screen, you can pretty much always touch one without even thinking about it. I think I would have to blatently try in order to fill that virus meter up the whole way.
I think that the game takes too long to get into the interesting parts. It felt pretty boring to me for a pretty long time until enough new enemies started spawning that were actually challenging to avoid. Fixing the bubble problem mentioned above, may help it feel more interesting at the begining of the game, or maybe adding in different modes of play (difficulty) to make it more interesting for experienced players. I didn't really want to start the game over again due to the fact I would have to play the slow parts all over again.
I really liked the boss. It helped change things up and came as an exciting suprise. Unfortunately I was unable to defeat him (I died on him (was killed.))
I liked how the tutorial intro text worked. It was nice to be able to move around and try out the different abilities while being able to read about them at the same time. I think that maybe the first screen should mention that you have to press the space bar. I had to button mash to find which button continued the text.
It was weird how directly after the tutorial, the static bubble just disapeared. It caused me to think I was going to die by the virus stuff and made me panic to the next bubble. Maybe you could just give it a velocity so it moves out of the screen naturally.
A pause button would be nice.Also, a confirmation text on pressing escape instead of just exiting would be a good idea to prevent accidental exits. It happened to me when I thought it would pause the game.
Overall it's an entertaining game and I really think that it has potential to be a fantastic game. Good job!