Colonial Marines modder finds big AI fix by changing one letter of code

Word is spreading over on ResetEra today about how an experienced modder of Gearbox's 2013 bomb Aliens: Colonial Marines discovered a way to significantly improve the game's AI by changing one letter of code.

Specifically, a modder who goes by James Dickinson published a note on ModDB last October explaining that they'd discovered a typo in a line of the game's AI code that, when fixed, notably improved the way enemies in the game track and follow targets.

The line in question, which at least one ResetEra user claims to have found in their own copy of the game's code, reads "ClassRemapping=PecanGame.PecanSeqAct_AttachXenoToTether -> PecanGame.PecanSeqAct_AttachPawnToTeather." When the "a" is cut from "Teather", at least one ResetEra user claims that the game's enemies become far more mobile and challenging.

"Why is this line important?" Dickinson wrote. "There are two reasons : 1) AttachXenoToTeather doesn't do anything. It's basically empty or stripped 2) AttachPawnToTether does ALOT. It controls tactical position adjustment, patrolling and target zoning."

When a Xeno is spawned, it is attached to a zone tether," they continued. "This zone tells the Xeno what area is its fighting space and where different exits are. In Combat, a Xeno will be forced to switch to a new tether (such as one behind you) so as to flank, or disperse so they aren't so grouped up etc. (*disclaimer* this is inferred opinion, I cant see the actual code only bits.)"

It's a good reminder that modders often play a vital role in deconstructing and improving games post-launch, even a game like Colonial Marines, which sparked a class action lawsuit against Gearbox and publisher Sega after it launched in 2013 looking much different than it did in promotional materials. Gearbox was eventually dropped from the suit in 2015.