Engine / System
Compatibility File modified so that all graphics card, regardless of model get by default the maximum quality settings available.
Maximum Shadow resolution increased
Shadow removal minimums lowered (more dynamics shadows)
Texture input switched to use maximum LOD values, Anistropic Filtering and higher quality Sharpening filter for distant textures
Particle System Spawn Rates, Life Times and LOD settings increased to remove resource limit restrictions
Many Particle Effects redesigned using different effects to increase visibility / quality of the over-all in-game effects
Lighting Models for Objects and Statics and many world objects improved through changes to Specular, Diffuse, Rim Lighting and Normal Mapping adjustments
Dead Bodies, Body Parts, Acid Splashes and Blood Splashes remain in the game world indefinitely
Spawning Volumes for dynamic and wave-attack sequences in the campaign have had a significant increase to the number of Xeno's and Mercs that can be spawned. Xeno's can
easily overwhelm an area if not dealt with immediately, and Mercenary Loadouts are much more varied, with more smart-gun/flamer/battle-file merc's spawning.
Tracer fire on all weapons switched to use the Sentry Gun tracer. This is an orange visible "bolt" and looks fantastic, really helping with gun on gun combat

Xenomorph Shared
Animations for Melee Combat (Win / Tie / Lose), Stance Changes, Jumping, Surface Transition, Stalking and Idling re-timed for better in-game behavior and movement
Damage Zones and Critical Hit amounts reworked so that Head Shots are needed to take a Xeno down quickly, with glancing shots doing little damage
Weapon Fire impacts and Deaths cause visual acid spurts/splashes that will burn and damage anything it touches

Xenomorph Soldier / Crusher (most actions for the Crusher are heavily scripted, but any dynamic actions use Soldier AI mechanics)
AI decision timing increased 1000% to greatly increase their ability to adapt to changing situations and react to new threats
Movement Speed, Acceleration, Weight, Jump Power and Flight Speed rebalanced so they are extremely agile and move swiftly around the cluttered levels.
Melee Encounter Mechanics modified so that they are almost exclusively used when it will kill the target. Xenos will wear down your armor with claws and kill you with an encounter
Pouncing reworked to improve movement around the map by reducing the maximum distance to consider jumping to. This leads to better object hurdling and wall/roof usage
Combat Damage significantly increased so only a few claw attacks are required to down a human

Xenomorph Lurker
AI decision timing increased 500% to increase their ability to outmaneuver you, without being impossibly difficult. Lurkers are truly terrifying!
Movement Speed, Acceleration, Weight, Jump Power and Flight Speed rebalanced so they are extremely agile and move swiftly around the cluttered levels.
Cover Mechanics reworked so they are exposed even less and move more often to stay hidden
Combat Mechanics reworked so that they will wear you down through several spaced attacks before finishing you with a Melee Encounter
Pouncing significantly nerfed to force them to run around instead of jumping across the maps. Increases their vulnerability crossing open spaces

Xenomorph Ranger
AI decision timing increased 500% so that they are much more reactive in their position choices. Rangers will quickly reposition to continue their barrage
Movement Speed, Acceleration, Weight, Jump Power and Flight Speed rebalanced so they are extremely agile and move swiftly around the cluttered levels.
Melee combat reconfigured to match Soldier melee combat. This makes Rangers more deadly than Soldiers!

Xenomorph Boiler
No changes have been directly made to the Boiler. Its AI is based on the Xeno Soldier, however its specialized mechanics already set a great pace in their short sewer
sequence in the campaign so I did not change them.
Their explosion however uses the generic acid damage mechanics and so are much more dangerous to groups

Human Shared
Animations for Stance Changes, Awareness and Idling reworked to look smoother
Situational Voice Acting reworked to make AI more chatty and informative. Calling out enemies, movements and kills more often, as well as making scenic comments
Awareness reconfigured to be much more realistic opening up more tactical game-play options
Vision reworked to allow sneaking and hiding to be used allowing stealth play in some sequences. AI reposition more often to get a better line of sight on their target
Gore Mechanics enabled for human corpses, allowing incidental damage and reactions to explosions after death
Weapons Carried by AI use the same Recoil and Ballistics of the player weapons, and as such effect how deadly they are with each weapon (see below)
Armor used by the AI use the same mechanics as the Player armor (see below)

Weyland Yutani Mercaneries
Teamwork tactics and information sharing reconfigured to remove their hive-mind like abilities. They share only what you hear them say
Weapon Damage rebalanced to reduce their threat level against humans and xenos. Greatly reduces the frustration of fighting them, and makes them much weaker vs Xenos
Health GREATLY reduced (they had 4x the health of the player originally)

Colonial Marines
Hive-Mind like ability reconfigured to improve the teamwork used by the AI in conjunction with player actions. Better use of cover, suppression and flanking
Weapon Damage rebalanced to increase their effectiveness in combat dramatically without making them overpowered.

Human Armor
Base damage absorption greatly increased so that taking fire without armor is extremely painful. Armor is now MUCH more important to stay alive
When fighting Mercs firing at non-armored locations is important to take them down quick (neck, arms, legs) with weaker weapons

Shoulder Lamp
Can be turned on for 4 minutes before it will flicker and turn off
When off, the lamp will not begin recharging for 5 seconds
Lamp recharges at about 1 Minute per second after that

Combat Pistol / Gorman's
Weight, Recoil and Ballistics (WRB from now on) rebalanced to more accurately match a PPK Pistol
Holding position moved forward a lot so the gun is not so big on screen. (can look a little funny when bringing up the Motion Tracker)

Service Pistol / Vasquez's
WRB rebalanced to more accurately match a Colt .45 ACP
Holding position moved forward a lot so the gun is not so big on screen.

Sub Machine-gun
WRB rebalanced to more accurately match an MP7A1 SMG

Pump Shotgun, Hick's Shotgun
Fires 00 Buckshot
Weight, Recoil and Ballistics rebalanced to more accurately match a Mossburg 500 Cruiser

Auto Shotgun
Fires #4 Buckshot
WRB rebalanced to more accurately match an Saiga 12 Shotgun

Double Barrel Shotgun
Fires 2 x Birdshot
WRB rebalanced to more accurately match a 411 Bear Claw Double Barrel Short Shotgun

M4A1 Pulse Rifle
Mk2 replaced with original movie rifle
95 ammo per clip, with ammo upgrade filling it to the maximum 99 (against Colonial Marines Field manual guidelines!)
WRB rebalanced to more accurately match a Light Machine Gun with movie 'canon' statistics

Hudsons Pulse Rifle
Matches Above, but uses 5 round burst fire instead of full auto

Assault Rifle
WRB rebalanced to more accurately match an M16a4 Assault Rifle
Default to single fire mode, with upgrade giving 3 fire burst mode
Flamer Fuel capacity doubled

Battle Rifle
Weight, Recoil and Ballistics rebalanced to more accurately match a USA Fielding M110 Sniper Rifle

M240 Incinerator Unit
I had a choice. Flamers, or Smart-guns. I chose Smart-Guns. As a result only Apone's Flamer is available in the campaign
Flame generation rate increased
Fuel Capacity increased
Fire Damage significantly increased

M56 Smart Gun
Assisted Targeting mechanics improved
WRB rebalanced to more accurately match its characteristics in the movie

XM-99A Plasma Pulse Rifle
shot count reduced to 2 per canister, but instant firing. With 6 canisters in reserve.
WRB made up from scratch ( )

Ripley's Pulse Rifle/Flamer
Pulse rifle is a fully fledged Pulse Rifle (same as above)
Flamer is a fully fledged Flamer (same as above)

Explosives
Damage greatly increased
Effects reworked to accurately match the damage
Physics shock-waveincreased

Firebombs / Fire / Incindiary
Burn time increased
Damage per second increased
Special effect increased

Sonic Electronic Ball Breakers
Stun Time increased
Lightning Sphere effect suped up