Gearbox Software Support offers details on a patch for the PC edition of Aliens: Colonial Marines that's now automatically available through Steam. This offers a number of single-player and multiplayer bug-fixes, as outlined in this change list:

General

• General user interface improvements.
• Various performance improvements.
• Fixed issue where a door may not function properly if a Xeno was killed while opening it.
• Addressed issue where players could become stuck in a close encounter after killing a Lurker that had pounced them.
• Fixed collision issue where bullets would not pass through certain open doorways.

• Fixed an issue related to clients incorrectly interrupting Xeno melee encounters.
• Addressed an issue where doors would sometimes not open properly.
• Addressed an exploit where players could melee while throwing a grenade or placing a claymore.
• Fixed some collision detection issues that could result from a close encounter.
• Prevented campaign pop-ups from appearing outside of campaign.

Campaign

• Fixed an issue that could prevent NPCs from getting on the elevator in the Sulaco.
• NPCs no longer attempt to open doors while being welded.
• Fixed issue where Raven could sometimes pass through welded door.
• Implementing a message to warn players that campaign progress will be overwritten if they try to start an offline campaign game from within the co-op campaign UI.
• Adjusted the distance between players before they're warped to the location of furthest player in co-op.
• Fixed issue where torch would sometimes appear incorrectly to co-op clients.
• Fixed issue where difficulty could sometimes become stuck incorrectly after switching modes.
• Fixed issue where co-op player would not recover properly after being saved from a close encounter.
• Fixed issue where Russian players could not drop into a co-op match in some missions.
• Updated late-game close encounter moment to disable player input, which could cause them to become stuck.

Multiplayer

• Resolved issue where campaign Motion Tracker could incorrectly in multiplayer loadouts.
• Fixed issue where clients would sometimes be invisible after spawning in No Hope in Hadleys.
• Multiplayer teams are now randomized (parties excluded) if percentage difference in scores is greater than 15%
• 'Switch Teams' option removed from the Pause menu.
• Corrected issue where server and client could get out-of-sync when switching out of a power-up while firing.
• Fixed issue where controller would vibrate during the scores screen if Rage ability was active upon match end.
• Fixed issue where Cloak ability would not conceal the Lurker when walking or jogging.
• Corrected bug where clients appeared to spawn outside of world before match start.
• Removed placeholder text from appearing on scoreboard in certain situations.
• Improved camera transition when Xeno enters a vent.
• Fixed issue where Xenomorph HUD could sometimes appear in the wrong color.
• Fixed issue with Spitter acid sometimes preventing players from deploying a Sentry Turret for a short while.
• Spitter's "Acid Spray" now originates from the mouth.
• Escape: Fixed issue where Xenos could spawn in unplayable space.
• Escape: Fixed issue where Xeno players could lose functionality if warped to next area while in a vent.
• Escape: Addressed issues where players would spawn with no weapon if they were the last Marine to die in Escape.
• Escape: Fixed issue where Cat-Like Reflexes ability would not properly complete in an Escape match.
• Escape: Improved timing and placement of warp locations in Emergency Evac map.