This game looks cool!
I think you have a nice aiming and shooting system, controls feel precise, the artstyle works really well and the characters' design is charismatic. I liked the joke about Oldgrounds!
The game needs more kinds of risks to increase the tension and give a bigger purpose to the playthrough. Maybe adding enemies getting closer to the player or characters that are more dangerous than others could help to give priorities to the player and a sense to the experience.
Incredible job, it was a good experience!