Having just cleared out the entirety of this lab, these are what I noticed (spoilered so that people who don’t want to be, y’know, won’t be):
1. Mono-level; no going up and down stairs like a maze.
2. Overall ‘smaller’, but perhaps compact is more accurate; it’s a crapload of rooms crammed into a single big square area.
3. Perhaps I was grossly unlucky, but very little ‘rare’ loot - (good) books were few and far between, mostly only on scientists; CBMs were entirely absent, except on scientists (again); no Mutagen or Serum in the slightest; no ‘advanced’ tech loot to be found. The only notable thing I found was a Rotary Evapourator, which is a heavy-ass tool which has Concentration 1 (used for Serum crafting, iirc).
4. It has a section (labeled ‘Subway Station?’ on the map, as an S) that leads to other labs of similar size and design via rails; I’ve yet to plumb these others, and if the loot is anything like this one, I’ll probably give it a miss honestly.
5. Filled with lots of zombies - in fact, ONLY zombies (and a few modest security automata, like manhacks and the ‘experimental’ drone that looks like a spider). Zombie Scientists are in excess, with other normal (Zombie, Tough Zombie, Fat Zombie) ones mixed in, and the occasional Hazmat, Shocker, and the newly-terrifying Bio-Operator. Get ready to slog through well 100 Zombie Scientists, hope your scalpel (which I also didn’t find, damn me) is ready.
6. Chemicals. Tons of them. Every chemical you can think of, and then some - Hydrogen, Acrylamide, Lye (Powder and Liquid), Zinc/Zinc Powder, Formaldehyde, etc. ad infinitum. For a home crafter, it’s pretty nice, assuming you can stand the craft times (and already have the books to tell you how to use these things).
7. No ID-locked rooms. The only exception to this is the ‘Subway Station?’, which has an ID lock.
8. You can only enter or exit via a single elevator in the epicenter of the lab.
9. More dangerous than a normal lab, if you’re susceptible to swarming; the hallways are tight and it plays like a game of Spacehulk, where any intersection can become a grave. Guns are not advised unless they’re silenced or you have enough ammo to kill everything in the complex, because they WILL hear you.