Hi,
I had fun with your game.
You did a good job of setting the ambience with your lighting and I enjoyed the overall wave-based gameplay. It felt fun and rewarding to make progress wave by wave.
I like that you had a currency system that could be used to unlock new areas and progress the story.
I enjoyed the introduction/text at the opening that helped establish the story and the player's motivations.
I dig the overall setting and I think the room design and corridors are pretty cool.
If you plan to expand on this in future, I would suggest adding some new materials to the level and tweaking the environment so it's a bit more dynamic.
I didn't realise I had more ammo/could reload the first time I played and I died looking for an ammo pickup.
Overall, I think you have a nice foundation for building this out if you choose to do so. The core loop is fun and you can pick and improve upon each of the individual elements of design as you go.
Good Job!