"Five Nights: Aerscam Mansion" has the following game mechanics.

Nights and Hours.
This game contains multiple nights of varying difficulty. In each one of these nights, a new enemy will become "active" and will try to kill you. Every night lasts six minutes in real life.
Even if the title says "Five Nights", after the fifth one you'll be presented with a mode called "Nightmare": an extra night where most of your enemies will be incredibly aggressive.

The Observation Zone.
This is where most of the game takes place. The Observation Zone is a room connected to the rest of the mansion by two hallways that can be illuminated with the use of the lamps next to them. It also has a strange artifact that lets Dorothy see the entire mansion and defend herself against the souls that attack her.

The Artifact.
A strange artifact that looks like a monitor. It lets you see the entire mansion without moving, allowing you to make strategies to avoid the enemies and survive the nights. By clicking on the buttons you can change the room. It will get corrupted for some seconds every time an enemy moves or when an enemy is in the room you're watching.

Audio Cues.
Being aware of audio cues is essential in this game. Heavy breathing, loud footsteps or distant screams may indicate the movement of some enemies. Music also changes according to the presence of multiple souls or how close they are to you.

Fear Scenes.
Some enemies have the ability to induce hallucinations in Dorothy's mind once they get into the room. This is called a "Fear Scene". You have to click on Dorothy's shaking silhouette at the right of the screen to calm her down, otherwise, she will lose her control and will get killed by the enemies.
Every Fear Scene increases Dorothy's Fear Meter.

Fear Meter.
Dorothy's level of fear can be checked with the fear meter. It increases not only with Fear Scenes, as some actions done by enemies can increase it too.
A high level of fear makes it harder to survive Fear Scenes, and tints the screen red.

Souls and Aggressiveness.
Every soul that attacks you in this game has a different routine, like moving randomly or in a fixed way. Some of them move fast and some others move slowly, some of them can induce Fear Scenes and some others can not.
As the nights go on, their level of aggressiveness will increase, making them more difficult to avoid while the game becomes more difficult.

Flashbacks.
After every night you'll be rewarded with a Flashback: an scene where the past events of the mansion are revealed. This will give you the answers to the unsolved mysteries the mansion has.

Custom Night Mode.
After finishing the "Nightmare" mode, you'll be rewarded with the Custom Night Mode, where you can play eight new challenges with fixed aggressiveness levels for every enemy, or make custom ones by adjusting the aggressiveness of every enemy, from 0 to 10, the way you want it.

Extra Menu.
After finishing the "Nightmare" mode, you'll be also rewarded with the Extra Menu, where you can see the enemies of the game, watch their jumpscares, replay scenes, and check some other content and guides too.