Not much is known about the Complex.
The Complex is supposedly under the Chicxulub Crater, which was made by the asteroid that ended the dinosaurs.
The dig is the standard environment that looks like a dig site. Different tools like trucks and drills can be seen in the dig. It has walls which seem to be quite unrefined and are mostly made of raw stone.
The lab environment looks like a rundown lab with aesthetics that make it look like it was abandoned. The lab is unique in a couple ways as you can only find syringes in the lab levels.
Garganta is a separate location mentioned in Rundown 3's logs.