THAT^. Also you could give it environmental stuff like fire, maybe add ladders, add something what would happen if citadel just stop to work, combines left and only some humans stayed. You know headcrabs also began to capture the whole place if you did play the game. Just try fitting in your own imagination. Or it would be even better if you had added d1_trainstation_04 to it as a continue to make it a bit bigger. Maybe, probably block some areas. Make a ravenholm-city17 out of it, idk.