Illyn Forest is the third map in Research 7, one of the campaigns introduced in Alien Swarm: Reactive Drop.
- Find a way past the blockage
There must be something to use in the caves nearby
- Find a way to bypass the gate
Burn the biomass away
- Rise the lift
You'll need to bring that lift up, hit the switch to activate it
- Defend the generator
The swarm seem to be attracted to something, defend the generator!
If they damage it too much the lift won't reach you.
- Get on the lift