It looks like the hallway before the elevator leading down to the Hydrofauna Studies Laboratories.
On the topic of the maps, I would have to agree with Text. Map with the grid (personally I use a setting of 8), use geometry for detail, and detail in a way that compliments your environment. Along with that, I have a few other suggestions.
Lighting is a big issue here. I know ti’s just WIP, but the lighting here makes the labs feel like this is before the incident. Since this is post disaster, you’re probably best off going for more atmospheric lighting. Firstly, I’d recommend knocking out a few of those lights- I doubt the electrical system would’ve survived the disaster intact, so chances are a few of the fixtures will be broken. Try toning the brightness of the lights down a bit too- if you’re having trouble, you could always just use lights from the stock maps (just make sure you give credit). You could also try adding in some of those red emergency lights that appear throughout the facility- it would make the lighting seem more varied, and less plain. Speaking of which, try adding some variety to your lighting. A lot of Black Mesa’s levels contain rooms lit by multiple fixtures, most of which emit different colored lights. It doesn’t have to be a huge difference, it could just be a light yellow and a light blue. Try studying the lighting within the stock game closely, and chances are you’ll have a better idea of what I’m talking about.
Another thing I noticed is the props you’re using. I mentioned detailing that compliments your environment earlier, and I’m going to take some time to elaborate. I did notice some props feel a bit “random” (i.e. placed as an afterthought, rather than with regards to the environment). Text also brought this up in his post, and I’m going to go into a bit of detail. Whenever you place a detail in the environment, ask yourself “would this prop make sense here?”. If realism is your goal, you’ll need to place props as realistically as you can. Once again, if you’re going for a certain type of environment, you can easily reference the game for inspiration. For example, it seems that you’re basing your level off of “Questionable Ethics”. So, I’d recommend studying how the environments within the chapter are detailed. You don’t have to replicate the details exactly (in fact, I would almost implore you don’t- the biggest reason the Hydrofauna Studies Labs was my favorite area in Opposing Force was the diverse blend of textures), but you can take cues from it. Detailing an environment does take practice, but the payoff is nothing short of rewarding.
I’m no mapping expert, but I have picked up on a few tricks over the years. Certain details can go a long way, and they can even be what separates your maps from the rest.