Hey , Here's my opinion on your game , good job first of all but here's what can be improved:
- Game is too slow , firing is too slow and kind of boring and you should make the gameplay pace faster and more exciting.
- You should add effects for bullets exploading and also sound effects.
- Maybe adding a minimap would be good.
- A room on the top right side doesn't lead to another room when going out of it's doors / empty space.
- Not very related to theme honestly ( i read the description and stuff)
- Maybe connect the rooms instead of grey areas between them
But overall good job on your first game 🎉