As a general rule, this game is all about stealth. Sneaking around and hiding when necessary will almost always be better than running, shooting, or making noise in general. Especially on the harder difficulties, the Alien and the other human/android opponents are easily attracted by noise - although you can sometimes use this to your advantage, e.g. by luring the Alien in killing some enemy humans blocking a way.
On your way through the station, you will acquire various weapons and items. Picking up blueprints will allow you to craft devices that help you with distracting or killing opponents, restoring health, or simply lighting the area to increase visibility. A short description follows.
- Flashlight/flashlight batteries: You acquire the flashlight early in the game, and it's mere function is lighting up dark areas to help you navigate. Usage drains the battery, and replacement batteries must be picked up. Warning: Opponents might become attracted once they notice the flashlight.
- Flare: Can not be crafted, only picked up. Can either be thrown or carried around, and will light up your surroundings even more than the flashlight. Warning: High chance to be spotted by opponents, especially when being carried.
- Medikit: Can be crafted. Restores a certain amount of your health.
- EMP Mine: Can be crafted. Non-lethal device that detonates on impact and disables synthetic opponents for a certain period of time. Can also be placed to become a proximity device. Warning: Has no effect against Synthetics in orange protective suits, which you will encounter later in the game.
- Flashbang: Can be crafted. Non-lethal device that detonates on impact and stuns humans/Synthetics looking at the explosion. Can also be placed to become a proximity device.
- Noisemaker: Can be crafted. Non-lethal device that (as the name suggests) can be thrown and keeps making noises to attract opponents; very useful to lure the Alien towards a group of hostile humans. Can also be placed on the floor, which will trigger the noise with a four-second delay.
- Molotov: Can be crafted. Lethal to humans, can be thrown and detonates on impact. Can also be placed to become a proximity device. In addition, the flame lights up the area around you, although to a much smaller level than e.g. the flare. Warning: Opponents might be attracted once they notice the glow from the flame.
- Pipe Bomb: Can be crafted. Lethal to humans and Synthetics, can be thrown and detonates on impact. Can also be placed to become a proximity device.
- Smoke Bomb: Can be crafted. Non-lethal device that can be thrown and emits smoke, thus reducing visibility. Warning: It will also reduce your own visibility, so make sure to plan your movement ahead.
To craft these items, you need a combination of various components, which you must pick up on your way through the levels, such as Scrap, Ethanol, Bonding Agent, etc. Sometimes these items can be found in plain sight on the floor or on shelves, but mostly within boxes and drawers. It is also important to notice that you can part-build devices even if you don't have all components to fully complete it - this way the parts will not fill up your inventory.
When picking up blueprints, you will typically encounter v.1 of those first. Deeper into the game, you might encounter v.2 and v.3 - those enhance the crafted items, by either increasing the area of impact, restoring higher amounts of health, or emitting a sound several seconds after placement to attract opponents.
Again, the game is about stealth. In theory, you can complete the game without using any weapons - but they do make the game easier at certain points. Different weapons are better suited for different types of enemies. A short description follows.
- Baton: The weapon you use when you have no other weapon equipped. Limited effectivity against humans and Synthetics, kills are pretty much only possible if the target was previously stunned. Not effective against the Alien or against Facehuggers.
- Revolver: Effective against humans, head shots result in instant kills (unless the target wears a helmet). Limited effectivity against Synthetics; again, head shots deal the most damage. Not effective against the Alien. Limited effectivity against Facehuggers, as it requires careful aiming against a typically moving target.
- Stun Baton: Effective against humans and Synthetics, but non-lethal; not effective against Industrial Synthetics wearing the orange protective suits, unless you hit them at the (unprotected) face. Enemies will be stunned for a limited amount of time, making them vulnerable for attacks with the Maintenance Jack. Warning: Stunning a human counts as a kill, thus eliminating your chance to achieve the Mercy of Prudence? achievement.
- Shotgun: Effective against humans and Synthetics, although Synthetics might require several shots. Not effective against the Alien. Effective against Facehuggers if shot at close range.
- Flame Thrower: Effective against humans. Limited effectivity against Synthetics, who will die only after burning for quite some time. Effective against the Alien - once hit, it will retreat for a short period of time, although this might require more than one flame burst. Very effective against Facehuggers.
- Bolt Gun: Very effective against humans and Synthetics, head shots result in instant kills for both. Must be 'charged' to get the most effective shot. Not effective against the Alien or Facehuggers.
Movement and hiding
When moving through the levels, you can choose to either walk, run, or crouch. Obviously, running is the fastest way, but will make the most noise. Walking also makes a fair amount of noise; to avoid any unwanted attention, crouch as much as possible. On the plus side, in certain levels (especially early in the game) you can actually run without the fear of being noticed - more on that in the next section.
Hiding is possible in lockers or crates - you will know that you are in a hiding place if you see a short animation scene when entering. Hiding in those spots makes you very difficult to find for enemies. However, if anyone sees you entering a hiding place, you will be found and killed (by the Alien), shot at (by a human) or pulled out and choked (by a synthetic) - so if you get spotted, run away as fast as possible and enter a hiding place only if you are out of sight.
Sometimes enemies will investigate the hiding place from the outside; you can avoid detection by holding your breath. Warning: Holding your breath reduces your health; you can actually die if you hold your breath for too long.
It is also possible to avoid detection by staying in dark areas, e.g. under a hospital bed or a between crates. If e.g. the Alien enters a room you're in for the first time, quietly staying under a hospital bed without moving might avoid detection. However, if you stay in that same room after the Alien leaves and returns for a new search, it will actually look under beds and in dark areas, thus almost always resulting in your certain death.
Under no circumstances should you use the motion detector while hiding; any nearby enemy will hear the beeping noise it makes and find you, even within a locker or crate.
"Save early, save often" - Al Lowe
Alien: Isolation lets you save only on certain save points, shown as old school emergency phone booths. The good news is that those save points are placed strategically throughout the levels, and almost always just before difficult parts. It goes without saying that you should save as soon as you encounter one of those stations. Warning: As saving does not stop in-game actions, there is a chance that you get killed if you try to use a save station while being pursued by an enemy. Thus, always try to shake off pursuers before attempting a save.
It is also important to understand the save game concept: The game stores a so-called "current save" and a "previous save". The current save is the one you saved last, while the previous save is from the time you saved before that. Important: If you ever load the previous save, it will become your current save, and the former current save will become the previous save. This is relevant when being forced to reload due to a death while going for the no-death achievement - more info below.
It is possible to save twice at the same save point, in order to have pretty much the same "current save" and "previous save". However, the game makes save points unavailable for a few minutes after using them, so you need to hide and wait before you can use them again.
Before we dive into the story, it is important to keep two missable achievements in mind, which would require you to play the entire game again if missed. Other achievements could also be missed during your playthrough, but can easily acquired by playing a certain level again.
Namely, these two missable achievements are:
Mercy or Prudence will require you to finish the game without killing (or stunning) a human. This basically means to stay clear of any humans in general, unless you are certain that they are not hostile. Use noisemakers and flares to attract the Alien or a synthetic to humans that might block your way, and have them do the killing for you; the achievement will only be voided if you kill a human yourself.
In order to get the One Shot achievement, you may not die once, neither by the Alien or any other opponent, nor from falling, an explosion, or being run over by a transit car. If you are being spotted by the Alien or get attacked by any other enemies, quickly pause the game and reload your current save before the death animation ends. Sometimes a death will occur too quickly for you to pause the game at the right moment, e.g. when you are being attacked by a Facehugger; you will know that this is the case if the pause screen does not include the option to "resume game" but only "load current save". If this happens, your "current save" is now spoiled and you need to load your "previous save". If you end up with both the current and the previous save being spoiled, you need to reload the "mission save" and continue the game from the beginning of your current mission.
Note: Killing an unarmed human will result in a game over screen and will also void your achievement.
As mentioned before, it is strongly advised to attempt this achievement on your playthrough on Novice.
So now, without further delay, let's dive into the story!