Here's how to access FST via the compound's sewage system. There's a couple of optional battles along the way
Echo Generation is a game that makes you think outside the box and come up with some creative solutions to the problem at hand. One such predicament jumps out at the player when they are trying to enter the FST facility through its sewage system. Both the task and its solution are fairly simple and straightforward if you remember to read between the lines and always keep your inventory in mind.
How to open the gate on the tunnel leading to FST
So you've blown up the alien spores, defeated the giant worm and gained access to the strange shed near the highway. Great, now it's time to venture behind the fence and take a closer look at the mysterious FST compound.
Entering the facility via the Elmer Lake door will prove quite impossible for the time being so you'll have to find your way through the sewage system. Here's how: Enter the new area through the newly unlocked gate off the train tracks and make your way towards the giant tractor. You can interact with the vehicle and Lilly even gets the option to climb on when the giant piece of metal comes to life and a new boss battle begins. This battle is optional as the tractor won't come to life on its own if you just walk past it.
Another optional battle is against the irradiated critters near the entrance. Killing them all will pose a nice XP hoarding opportunity. If push comes to shove, I suggest that you first kill the little ones (a sentence I never thought I'd write) as they can summon more fully grown creatures.
Once you've cleared the path to the centre opening, you'll want to change your party composition. Choose Blopo-11 as your pet companion and you'll go through the bars with ease.