I just played it, I got to teh scientist room, and that's it?
You're almost there, don't start mapping the next levels until this one is greta, first:
alot of stuff is too big, the air vents at the start look too big, unless you put in soem supports around them.
The architecture shows promise, you've obviously just finished either OP4 or Blueshift, some of it is reminiscent of those games (not a bad thing at all), you need to work on teh areas that look bland, the ladders are ok, but there's something about them, try aligning the textures on those handrails, and making them thinner.
The scientist room, the wires are way too thick, make them 1 unit square, that is a good wire size, and the computers, some textures are too stretched, use another one, or make the computer smaller, the beams in teh corridor, the side struts don't meet the main central one, i don't know if you were trying to avoid high r_speeds, but fix them because they are noticable when you climb up there. make the beams a func_wall or something, but i'd say just have them as brushes, and put some lights up there, in odd places, so you get some cool shadows, try and make the whole thing a bit darker, as it's not edgy enough with teh amount of light. depends what you're going for, but as it seems liek some bad guys have broken in, i'd have more lights blown etc.
teh 1st time i played through i climbed up that ladder and snuck past the guy (nice gameplay, thumbs up), i then shot the other two, but i'd have a trigger once just before you go around teh corner, have it trigger an ambient_generic with a grunt reporting in, saying it's all clear etc.
And the door taht the two came out of, i managed to get in there, and couldn't get out, so maybe texture it a little, and have another door that looks liek the grunts came in that way, but have liek a trigger once on the inside so you can get back out but not in.
All that aside, it shows potential, the gameplay i witnessed was thought out and well executed, some nice areas, but they need some p*zazz! y'know.
i'll give it 3/5 for your first attempt, but get cracking on doing it up, i'll help if you need advice/help/textures/models/testers.
Nice Job!