Hey man, I did my full 10-minute review during my Twitch Stream Friday night (twitch.tv/aaknox), but I'm going to summarize what I said during my review:
Art: The art on your gun and monsters are fantastic. The only disappointment is in the loss of potential that you could have done to the body lining had you chose a different color palette from yellow and purple.
Animations and Controls: The gun projectile effects are very nicely done. You also did a good job with the animations for the enemies. The controls were very simple to understand and use.
Sounds and Music: The sounds for the gun are spot on. I cannot say the same, though, for the background music. If you're going to loop a short music clip, I suggest you make the music loop is long enough and syncs fluently behind itself.
Overall gameplay: Although you explain the intended story behind this game, the dying aspect in this game didn't work into the theme for this week. If the antibiotic is being tested to its strength, then the gameplay should have explored that idea in some way (for example: allow players to gain bullet strength or have a spread shot after killing x amount of enemies).
Hope this review helps you grow!