What Spirit said, pretty much.

OK -- pretty competently assembled. But the main difficulty comes from almost always being nearly out of ammo, which isn't the kind of challenge I mostly enjoy.

Very respectful of id's style, this looks like a map that could have been in the original game. It's a bit weird to have so little of base transitioning right away into a dungeon for the rest of the map, but why not? As Mike said, it is a little short on ammo but it's totally manageable if you're careful about your accuracy. The two secrets are absolutely unnoticeable. I had to noclip to find them and even then, I couldn't figure out how to open the one [SPOILER] behind the stained glass. [END SPOILER] Other than that, nothing special.