Kitty Mod is an ultra-hard Alien: Isolation mod intended to be unrelentingly difficult, primarily created to provide Alien: Isolation speedrunners with the ultimate challenge. While Kitty Mod can be enjoyed by casual players as well, many of the changes are speedrun-oriented, either to skip long, tedious sections of the game, or to render common speedrun tactics and exploits useless. There are also numerous inside jokes present throughout the mod that may not make sense to those outside of the speedrunning community. Nevertheless, if the ultimate Alien: Isolation challenge is what you're after, Kitty Mod is for you.

For people who are interested in speedrunning, there is a official speedrunning page on speedrun.com: https://www.speedrun.com/kitty_isolation

Outlined below are the changes Kitty Mod makes to the base game:

Player Attributes:
• Scrap stack limit increased to 250.
• Medkits restore 100% of Amanda's health regardless of blueprint version.
• Smoke bombs, noisemakers and flashbangs yield two items upon crafting.
• Pipe bombs, molotovs, EMPs and medkits require 5 less scrap to craft.
• Noisemakers, flashbangs and smoke bombs require 5 additional scrap to craft.
• Medkit stack limit decreased to 4.
• Revolver ammo stack limit decreased to 36.
• Shotgun ammo stack limit decreased to 12.
• Flamethrower fuel stack limit decreased to 250.
• Boltgun ammo stack limit decreased to 8.
• Stun baton charge stack limit decreased to 4.

Weapon Attributes:
• Revolver shots stun the alien similar to the shotgun.
• Shotgun does slightly less damage to androids.
• Flamethower fuel consumption rate is decreased.
• Boltgun shots penetrate enemies and inflict damage on enemies behind them.

Enemy Attributes:
• Alien has hypersensitive hearing and vision and will immediately notice Amanda, even at extreme distances.
• Alien movement speed increased, both in the vents and on the ground.
• Alien moves towards Amanda faster if the player turns their back to it.
• Alien drop rate significantly increased.
• Alien no longer walks while searching for Amanda or being threatened with the flamethrower, but instead runs.
• Alien is much more likely to initiate a "hold breath" QTE when Amanda hides in a locker.
• Alien health doubled.
• Alien regenerates health significantly faster.
• Androids have hypersensitive hearing and vision and will immediately notice Amanda, even at extreme distances.
• Androids no longer walk but instead run.
• Androids are much more likely to initiate a "hold breath" QTE when Amanda hides in a locker.
• Androids have slightly less health.
• Humans have hypersensitive hearing and vision and will immediately notice Amanda, even at extreme distances.
• Humans have significantly increased fire rates when shooting.
• Humans start to become hostile at much greater distances.
• Humans of the security and riot guard classes have additional health.
• Humans are much more likely to initiate a "hold breath" QTE when Amanda hides in a locker.

Mission Attributes:
• Enemy placement has been altered in several missions.
• Additional enemies have been added to some missions.
• Various dialogue and scripted sequences have been removed to decrease run time.
• Forced walking sections in several missions have been removed to allow Amanda to run.
• Some blueprints have been changed to a different blueprint.
• Several non-random loot items have been moved to a different location.
• Several new non-random loot items have been added throughout the game.
• A lootable corpse in Mission 3 was moved to a different location.
• Several doors have been unlocked or removed completely to allow quicker access to certain locations.
• Several door braces have been moved to either allow for quicker access, or to prevent a known speedrun exploit.
• Most door codes have been changed and can be found in their respective terminal entries.
• Some door overrides in Mission 5 have been removed.
• All door and terminal hacks have a 6-symbol callback code regardless of access tuner level.
• Hack tool selection angle has been reduced to make tuning into the correct hack position more difficult.
• Countdown timer for all hacks has been lowered except for the Apollo core hack, which has been raised.
• Various save stations have been moved to a different location.
• Save station in Apollo core has been removed to prevent a known speedrunning exploit.
• Time between saves has been lowered to 30 seconds in Mission 6.
• Several gas canisters have been moved to a different location.
• Gas volume in the Lorenz server control room has been moved to a different location.
• Various trigger boxes have been altered to decrease run time, increase difficulty, or surprise the player.
• Cable order for the electrical junctions in Mission 12 has been altered and is reflected in the subtitles.
• Cost to use save station in the Lost Contact and Safe Haven DLC missions raised to 5,000.

Texture and UI Attributes:
• Hack tool screen color altered.
• Subtitle text color altered.
• Intro loading screen altered.
• Main menu text color altered.
• Main menu background video altered.
• Various menu options renamed.
• Fox intro video altered.
• End credits altered.
• Loading icon altered.
• Saving icon altered.
• Motion tracker screen color altered.
• Radio scanner screen texture altered.
• Color of some fire effects altered.
• Color of light emitted by lit flares altered in several missions.