Molotovs should always scare the alien

[Spooky Bunyip]

Does there just come a point where molotovs are useless? My alien seems to be running right through them now and I've only scared it away with one or two over my runtime.

[NinthElement]

Molotovs are always equally useful. However, hitting the alien with one doesn't guarantee you won't get caught by the alien while he is running for a vent. Also, if he is moving too fast he might not slow down before he collides with you.

Having said that, I have on rare occasions experienced where he took a direct hit while standing, and then he just ran over and grabbed me anyway (no vent behind me). Steve does unexpected stuff sometimes, it's all part of the fun.

[AmesNFire]

Whenever you use an item on the Alien, it gets 'skill points' towards resisting or ignoring that item. It also gains points if you keep using the same ways of hiding (the supposed 'lockers = death' thing) because it eventually "learns" what you're doing due to the Alien AI.

I believe the flamethrower also contributes to the Alien resisting fire.
Realistically, your best possible solution to any encounter with the xenomorph is simply not to be detected in the first place.

[NervXT]

Originally posted by AmesNFire:

Whenever you use an item on the Alien, it gets 'skill points' towards resisting or ignoring that item. It also gains points if you keep using the same ways of hiding (the supposed 'lockers = death' thing) because it eventually "learns" what you're doing due to the Alien AI.

I believe the flamethrower also contributes to the Alien resisting fire.
Realistically, your best possible solution to any encounter with the xenomorph is simply not to be detected in the first place.

This is the correct answer. The developers wanted to make it appear as if the Xenomorph is learning and so will eventually start to ignore your attempts to distract or hurt it if you rely on doing so too much. The same is true of hiding locations. Even though the Xenomorph is never told where you're at, it will eventually be encouraged to be more proactive in searching hiding spots you're frequently using.

These mechanics are really intended to be a last resort option. You hide when the Xenomorph is in your immediate vicinity, use distractions to send it elsewhere if you really need the extra buffer to navigate to the next area, and use fire when it catches you out in the open. When the Xenomorph is gone or not in your immediate vicinity, you can walk around to help traverse an area more quickly. The only real difference between crouching and walking is that the Xenomorph can spot you much quicker at a distance if it looks in your direction and you're standing up. The sound difference is fairly negligible. Higher difficulties will decrease its reaction time to things it sees or hears.

[JefferyNothing]

Basically if you use certain items or weapons too much it'll eventually start to ignore them. However I've never seen the flame thrower be less effective in the 5 times I've completed this game. It always hates it and I use it a lot.

[AmesNFire]

Originally posted by JefferyNothing:

Basically if you use certain items or weapons too much it'll eventually start to ignore them. However I've never seen the flame thrower be less effective in the 5 times I've completed this game. It always hates it and I use it a lot.

From what I understand the flamethrow is treated like throwing two molotovs directly at the alien and does "more damage" in a sense.
So the Alien will always retreat from it until it's gained enough 'skill points' to retreat a bit down the hallway and try again in a moment instead of a full retreat; which eventually turns into the xenomorph ignoring the flamethrower.

Presumably you noticed the xeno getting a tad more aggressive and recover faster near the end of each run.