I really liked the game! The part I liked the most was the aesthetic, graphic and audio wise, which was very convincing. The gameplay was engaging. I died once and I didn't feel frustrated, I wanted to beat the game, which is always a good sign!
Feedback: I think it might have been part of the overall feel you were going for, because older games absolutely did this, but it felt kind of weird how the blue enemies hit you instantly upon seeing you. Maybe having some sort of visual cue, like a change in sprite, could help the player know when they can peek safely. Also, I'm not sure if headshots are a thing in this game, but that could be a cool feature to add!