I like the aesthetics a lot - both the virus theme, which is a really unique setting, and the retro vibes. (I don’t mean retro just because it’s pixel art… something about the graphics and gameplay feel old-school to me.) I like the variety of weapons too1
I do think some more depth is needed to make the game hold the player’s attention for longer. Some different stage layouts would be nice, maybe, or some more enemy types. Right now they’re all the same basic fodder enemy, and because of that there isn’t a huge difference between weapons in terms of how hard the game actually is. The ranged ones are best because they drain your health up close, but it doesn’t matetr which you pick really. (If there are harder enemies, I guess I didn’t get that far.)
Overall, a fun little experience!