Really cool game, loved the commitment to the old aestethic. The art is fantastic, really nice pixel work, especially in the opening. The main issues I had with it were the enemies spawning on top of you at the bottom left and right doors, felt a little bit cheap, would like a bit of a warning like the top door.
Other than that, can't wait to see how this game develops, I included it in a recent video and would love to come back to it when it gets more updates.
I have some ideas about the sides. But I'm not sure if they will work. I'm limited on what I can do. I'm already close to maxing out sprites and frames. I may try palette switching and do a lighting effect around the door. As if a light is flashing. But my bg colors from floor to floor will start to look the same. Fun problem solving. First I need to figure out what to do with the B button.