2. The Xenomorph Has Eyes In The Back Of Its Head (Sort Of)
The Xenomorph isn't known as the perfect organism for no reason. Anyone who's seen this acid-blooded hunter in action in any of the Alien films or played Alien: Isolation for any length of time will be able to attest to this.
The creature's heightened senses easily allows it to hunt down its prey and efficiently take them out. In the game, this means the creature can detect gunshots, footsteps, and even the beeping of the motion detector if it's close enough - 1.5 meters to be exact. It does not, however, have any sensors when it comes to its tail.
Don't think this means that you can get around all your alien-based troubles by simply walking behind it. The developers were aware that some may try and do this, so as a countermeasure they programmed in short range ray tracers that let it look behind it.
The Xenomorph literally has eyes in the back of its head - and that makes it even more terrifying.