From Halopedia, the Halo wiki
Universe and lore
On the remote world of Erebus VII, at the very edge of human-occupied space, an ONI research facility which was once teaming with researchers now lies eerily vacant. Although the hostility of this world had been initially considered by its team leaders, it is tragically clear that a great many ‘things’ had simply not been taken into account. Initial surveys of this area were bold and promising, but it quickly became clear that these reports were far more hubris than logic.
Abandon is an asymmetrical, close-quarters small scale 4v4 map.
The map features a three story building in the center of a dark forest environment, allowing for some long ranged combat but offering more short range skirmishes due to the trees and tight spaces. It features 3 man-cannons (one in each main structure, and one inside a tree between them) and ramps leading to all levels.
It was originally going to feature organisms called meat loops, muscle humps, gas sacks, smokers, and momma trees throughout the various different iterations of the map. Some of these organisms can be seen in the concept art.
Abandon had three distinct iterations. The first was the balls-to-the-wall alien greenhouse version. There was a dead monster-like creature on this map that you could use as a ramp, and there was a story that went along with it—something along the lines of: the monster attacked, killed the scientists, and then died from injuries it sustained. There were numerous subplots and supporting elements scattered around the map and in the skybox.
The next iteration featured smaller animals trapped in containers underneath the map as the reason for the science team’s ‘disappearance,’ and early concepts show that the place was pretty badly assaulted. This version represented the first paring pass that reined the environment into a simpler and more believable statement of the original theme and cropped out some of the unnecessary components (we wanted to get back to what we really liked about the original concept art).
The final iteration was an even tighter trimming of things that weren’t needed or weren’t working. The building’s interior looks relatively pristine compared to where it was originally, which is definitely to its advantage from a play-ability perspective, because it provides a stark difference between inside the structures and the wild flora that grows outside it.