One-Letter Typo To Blame For Aliens: Colonial Marines' Bad AI

Image: Gearbox / SEGA

Thanks to the work of modder James Dickinson, Gearbox's notoriously awful Aliens: Colonial Marines can now be played as something other than a form of punishment. You can imagine Dickinson's uncovered some nutty bugs in his time poring over the game, but none hold a candle to a single-letter typo that lobotomised the Xeno AI.

Dickinson wrote about the typo in late 2017 when he first discovered it, describing it as "the biggest BUG in the game":

Inside your games config file (My Document\My Games\Aliens Colonial Marines\PecanGame\Config\PecanEngine.ini) is the following line of code:

ClassRemapping=PecanGame.PecanSeqAct_AttachXenoToTether -> PecanGame.PecanSeqAct_AttachPawnToTeather

Yep, "teather" instead of "tether". According to Dickinson, the logic attached to this is rather important, allowing the AI to "[control] tactical position adjustment, patrolling and target zoning".

By simply removing the "a", the AI is transformed — it will happily flank you and "disperse [Xenos] so they aren't so grouped". Which, as you can imagine, makes a big difference.

There's A Reason To Play Aliens: Colonial Marines Again

I know it's a tad impossible, but hear me out. Let's go back to the launch of Aliens: Colonial Marines (ACM). Remember the fury, the outrage, the disappointment. Most of all, remember what was missing.

Read more

If you ever wanted proof as to how big a shitshow ACM was, it doesn't get much better than this.

A typo found in the INI file after all this time appears to be one of the major causes for terrible AI mechanics in the game. Thankfully typo's are easy to fix! [ModDB, via ResetEra]


Comments

    Is there an example that shows how much this one bug fix changes things? I had so many issues with the game that I struggle to believe that this fixes the game, even at a fundamental level.

      Sam Machkovech has a write-up on Ars where he mentions it dramatically improves the Xenomorph AI and states "the difference is night-to-day"

      Here's a video made on the issue (Curiously, it was posted a day before this article).
      https://www.youtube.com/watch?v=v_SdkxbgOV0

      The gameplay footage comparison between playing against the broken AI and the fixed AI starts at 3:45.

    Jesus, this has to be up there with glitches on discs such as the Baldurs gate one where opening a single door would crash the entire game, or when Warhammer Online shipped a batch of discs with a corrupted EXE file to actually launch the game with XD

      Those games got patched though.

      This bug seemingly was not; it actually sounds like this "mod" is really a patch from an unofficial source.

        Oh I just mean in the sense of a gamebreaking bug launching with a game... but yeah they were patched soon after. Though the Warhammer one should've stayed a bug because BOY that game sucked...

      Oh wow. I remember that Warhammer Online issue.

        We getting ollllllld thatteemo... lol

          Those dark days when everyone was releasing an MMO and every one before release was called a "WoW Killer".

            I didn't mind Warhammer Online. It showed the way with Public Quests, so added something new to the genre. It just pushed you into PvP with little way to advance without it, which I didn't want.

            Was the only MMO where I enjoyed battlegrounds though, mostly because I had a simple but effective way to take early control of one of the early maps.

    and NASA lost a Mars lander because one lot of contractors used metric and another lot used imperial, sometimes human error happens. Not sure a simple typo is conclusive proof of "how big a shitshow" something is.

      oops that was meant to be 'orbiter', see, human error at work. hehe.

      It shows how inept the studio was that something so simple made it into the retail copies even after several patches. Youd think there would be processes in place to pick up something so simple. Clearly not.

    So there was some half decent AI, but nobody noticed it was misbehaving in a big way? Seriously lacking in the QA department there.
    (Well duh, everyone says)

      That's not really how QA works

        ...yes it is??? They have play testers to do quality control generally through a games construction? That's exactly how quality control/quality assurance is meant to work.

          QA tells the devs whats wrong.

          Its up to the devs to fix it.

          QA could have told the devs this was an issue but they dev team instead decided to leave it as it. QA does not fix the game, They just tell them whats wrong.

            I'm well aware of that. It tells them what's wrong so the devs can go fix it, that's why they have playtesters. Noone expects the playtesters to go fix it now do they...

              Thats the point im making. QA could have made the devs aware of this. But the devs either through publisher pressure or of their own volition could have decided not to fix this.

                Or, in the millions of lines of code, failed to identify the single letter causing the problem... Thats a pretty small needle in a pretty big haystack.

                  It wasnt in millions of lines of code.

                  It was in an INI file containing around a page of settings.

              Im not disagreeing with you BTW. Just adding to your comment :)

                Ah ok my bad, apologies, I completely misread it :)

                  All good man. Ive made the same mistake before. I always feel shit afterwards. Its why i always take a few moments to read over stuff rather than jumping straight into commenting :)

            It depends on the company / team. In many it's like that, but in others the QA/E (e.g. myself) is capable of managing code and can debug or even fix/suggest errors - depending on the level of freedom they have. I'd never again work in a company where the QA was forbidden from code changes.
            "Playtesters" would come well after component QA, and if the organisation has even the basic of respect for their quality engineering then something like this would not have QA approval and would not be released.
            But then, going by the comments, perhaps Gearbox is not one of those...

        Could you elaborate on your comment? I'd like to understand your perspective.

        As I see it, the "intent" was to have the enemy move a certain way based on player location, environment and such, for example flanking and charging. Clearly this was not working "as intended" and it should have been recognised, especially as a core component of the product.

    PC Gamer has a write up about it with gif/video of it in action. it doesnt automatically make the AI great, as its still pretty shit, but it does so an improvement

    Well shit. I own this on PS3, so I’m probs not gonna get any benefit from this, but it’d be nice to be able to play it and enjoy it.

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