I'd like to chime in with some additional constructive criticism mainly about detailing. Your brush work is okay, and you seem to have some understanding of how to use tools like decals, overlays, rope keyframes etc which is a good start.
Your detailing is a bit too random and directionless, when you design an environment you need to really think about the purpose of it and what would fit there. For example in the bathroom you have a visible wire connecting the lights, but this is a tiled ceiling which means it's superficial. Everyone knows that tiled ceilings like this have wiring running behind them, the tiles are just a cheap way to keep them accessible for maintenance. The map as a whole doesn't feel like a warehouse, it feels like a military base and only really one room in it actually feels a bit like a warehouse but that's because it has some shelves. Also be careful with scaling textures! Avoid scaling textures above 0.25, the bathroom walls look terrible because they are scaled too large. You won't notice in low detail but for people playing in higher detail it sticks out like a sore thumb.
My recommendation is moving forward you should try to look at photographs of real locations for reference, look at architecture styles, structural feasibility. Is this room big enough to need extra supports like pillars or trusses? Do these walls seem thick and strong enough to support the ceiling? What are these pipes for? Where should they lead? What purpose does this room serve and what needs to be in it to make it a functional place? Why is this wall made of rock?
Also when it comes to things like lights etc try not to use the default values, adjust the opacity of things like env_spotlights so they feel less artificial and blinding. Lighting is pretty much the most important thing with regards to making the map feel and look good, it's just as important as textures and models, so you can't just throw lights around in a few minutes and just be satisfied.
Gameplay wise your map was big enough but could have more flow, most rooms were dead ends, and all the doorways were very tight which results in bottlenecks, also there's a serious lack of weapon spawns, you need at least 8 weapon spawners and probably 16 ammo spawners in a map, one weapon for each slot and two ammo crates for each weapon. Take a look at Facility_backzone and how plentiful the weapons are which makes for much better gameplay. Most rooms should have a weapon, it gives people an actual reason to go in them.
Last but not least, there was no optimization, do not just throw a box around you map to seal it. You need to seal the map as it is so that visibility can be compiled correctly and always compile VIS on 'normal' for final compiles. At the moment people have to render the entire map wherever they are which means poor performance.
Also you distributed your music script in the wrong folder, it should be in scripts/music.