I really liked the sound and overall vibe of the audio, especially the music. I actually think the concept is pretty interesting, although I admit I'm not entirely seeing why it's bugs we're fighting. But the overall retro vibe is pretty cool.
The main things I'd consider changing would be making each level just a tiny bit bigger so we have more room to run around, and just adding some hit effects like shake, flash, and/or sound when hitting enemies to make it more obvious we're actually doing damage.
Other than that, though, I really like the look and vibe of it, and I can tell you spent a good amount of time on making the levels look nice!