Love the aesthetics and sounds, nice work there!
I think there is a major flaw in the level design: by shooting constantly upwards, there is no way the herd of pathogens will advance for the first 13-14 waves. This makes the game so easy that is boring. I'd consider putting a barrier there to avoid this "exploit".
Besides that, it's a solid entry, and I had a lot of fun playing it. Congrats!