For many, Aliens: Colonial Marines was the epitome of disappointment. Shown off at trade shows and in a string of trailers before launch, the final released shooter from Gearbox did not live up to expectations—its graphics had been downgraded, it's AI was weak and would often get trapped in the environment, and, for an Aliens game, it lacked tension.
Well, TemplarGFX has tried to mod away as many of the problems as they could. Their huge mod "reprograms and rebalances Xeno AI, Human AI, Weapon Mechanics, Ballistics, Animations, Shaders, Particles, Decals, Lighting, and engine features to get the best out of the game possible."
According to the mod's ModDB page it's the Xenomorphs that have seen the most changes, with the modders working to "[fix] their behaviour and mechanics to make them truly terrifying foes to face, dramatically shifting the tone of the entire campaign.".
You can read the full list of changes over on that page. Reading through them, it looks like the Aliens all react significantly faster to your presence, as well as leaning more on cover to cover movement in the dark, instead of attacking you in the open. Their armour has been changed, too, so anything other than a head shot is now really only a glancing blow, meaning if your aim is off you're going to burn through ammo and likely get eaten.
Oh, and the aliens' claw damage has been upped so you'll be downed in a just a few hits.
All the weapons have been fiddled with to make them more deadly, like the more accurate smart rifle and the more damaging flamethrower, and offer you a greater chance against these newly danger-filled aliens.
The actual campaign missions and maps stay the same but it will be fascinating to see how this rebalance ups the thrill of the original game.