It isn't popamole because the only enemies that fire back, the humans, are too stupid to take cover.
I'm trying the "Crew Expendable" DLC. For those that just want a tour around the Nostromo, this seems to be their ticket.
It starts just after Brett has had his brain ventilated, and the crew are trying the "flush the thing out through the airlock" trick. You get to choose to play as Ripley, Parker or Dallas.
First part of the DLC involves collecting equipment on the topmost deck. It's small, but the next deck below is not. You get a motion scanner (different than the one in the main campaign, and unusable in lockers) a maintenance tool (?) and a flamethrower, with flamethrower fuel scattered all over the ship...in some bizarre places. One bottle is located right next to the ketchup in the kitchen, I guess someone likes their spaghetti "extra spicy".
Ian Holm's voice actor replacement sounds much better in the DLC than in the main campaign, while Harry Dean Stanton clearly sounds old and tired.
The other voice actors do a good job, with Weaver being the clear winner.
Gameplay on the lower deck is similar to the main campaign, the monster stomps about, hides in vents, you have to access a couple of computers, go to a location to find Brett's body (?) and then enter the airvents. I lasted about 40 seconds in there before dying, and instead of a "reload" option I got a "load last checkpoint" option, which didn't work. That's the second time playing this game that the save wouldn't load.
Oh, and when it comes to non-relevant talk and bodily sounds from models, their faces don't. move. at. all. Listening to Ripley cough like she has lung cancer while making this face is kinda lulzy: