It was fun!
I had a lot of fun with this game! Ammo seems to drop at a really good rate- so you are constantly having to switch guns and you only have to use your pistol when things really get rough. I like being able to move through different rooms and find your way through the complex- it give an adventure feel to a shooter game.
To address some of the complaints that others had about getting lost easily, you might include a simple mini-map that resembles the Map/Compass from the Zelda series.
If you were interested in continuing with this idea, I think using the same basic system with a large area to explore, a map, and an inventory and mission objectives would make for a really cool game.
I had fun! Thanks for taking the time to make it!