Please don't feel bad or guilty. Anything to do with creating and art is about learning and expressing a unique vision of your creation. You being negative or me will not help your inspiration
The map works ok, and there's only a couple of small problems. In the image below, monsters would not go through the gap to the arrow. If I moved to the pathnode directly below the gap they did, so I suggest place a pathnode.
The Trader area has too many weapon pickups, maybe 1 pickup would be ok. Pickups in diverse areas will force players to go all around your map. But the way the map is now, players will stay only at the trader area.
In the image below add some zombie volumes because the zombies came from distant volumes and that took a some time and was a little boring.
Some suggestions.
In the image below, the Trader Area the lighting is atmospheric, shadowy, with light and dark areas. The shadow under the walkway and the light coming from outside look realistic. I like the lighting in Trader area of the map. It fits with KF Ambience, dark and shadowy.
The map outside is too bright -but- that is only my opinion. I would also suggest making the skybox darker, but you could place a light in there, perhaps like the moon. But definitely darken down the outside. Then under the lights, it's bright but elsewhere shadowy, similar to how it is at night.