Not a bad little base snack. Theme is good and I thought the low lighting was fine except in a few places where it made certain doors hard to see, e.g. SK door; or the door towards the exit which isn't well-lit, highlighted and doesn't strike the player as important.
I like the flanges and rivets on the pipes. The rivets seem just a couple of units too tall on the smaller ones, though. And it would have been good to turn them into func_detail_wall or func_detail_illusionary as they produce a lot of polys where they touch the flanges (check with r_showtris 1).
There's something that bothers me in the big slime area. I think there are too many thin pipes or their placement looks too artificial, sticking out of the walls and far into the room. Something along these lines.
I like the nonlinear approach, but I can also see how this can be confusing, because it's not always obvious where to look for the buttons. Adding to this is the fact that the level is basically divided into two parts with one-way connections. The slime dive is okay to use the first time, but afterwards I would have wished for a shortcut that bypasses the slime, not least because the biosuit is gone by then. Unless there is one and I simply missed it, but I don't think so.
Strange not to have the SSG, but then again, it might have been in a secret; I only found two or so.
Technically, not doing a fullvis on this map is a no-go. Like it would have taken long...! And my standard broken record complaint: the map could have worked on vanilla ports just fine. All it would have taken is removing or grouping two or three brush models and running a fullvis to bring it down under the limits. Easier than in any other recent map.
Also, please get someone to playtest the map before release next time. It helps a lot.