Here are some things I've noticed after completing it earlier today.
The first part of the map is by far the hardest. As soon as you get past the first area, the map becomes much easier. The only real threat past the first area are five or so Fleshpounds that randomly wander out when going to shut down the last part of the generator. Its easy to rlose past them though.
There are barely any enemies in the map after clearing out the spawners in the first area. The three Fleshpounds wandering around right in front of the facility's entrance were not much of a threat when Anti and I could safely blow them away with LAWs while we were on a hill. Same with the eight Stalkers that came out two at a time in the facility's top floor. Three people with Hunting Shotguns make quick work of them. In v2, there would've been quite a few Fleshpounds at the entrance on both sides of the gate to the entrance while some Gorefasts roam around the street. Stalkers would've flooded the top floor and been accompanied by Crawlers or Gorefasts.
The constant fire damage while escaping the self-destructing facility on the top floor is annoying. The speed decreases you take as your health gets lower makes it hard to escape after your health has reached 60% or so. Even constantly self-healing only helps so much before the constant fire damage makes it impossible to reach top speed again. Armor is a big help, but if you don't have it, you're pretty much screwed unless you drop all of your weapons and go Medic.
The Patty does not appear after escaping the facility. Our game ended with me trying to blow up some static helicopters with a LAW while Jyrki botched a grenade suicide.