Nice game for your first try!
You could improve it by adding more pickups when killing the flies or something similar.
Viewing post in Fly invasion jam comments
Thanks and thanks for a suggestion! I was planning to add more enemies, increasing the difficulty over time and adding pickups that'd improve shooting (firing rate/different guns). I started developing late, so there was a big time pressure on even releasing the game :)
Hopefully I'll add more stuff in the future.