This page lists the type of areas available in Amnesia, and what they do.
Script: Trigger's a script when an object (like the player) looks at it, collides with it or interacts with it.
PosNode: This is used in combination with Rope areas, to show where the rope ends.
Flashback: Trigger's a flashback sequence.
Sign: Displays text when the user looks at it.
SlimeDamage: A damage area for the red slime (The Shadow).
Examine: This gives an area a description when it is examined. Also allows for different descriptions depending on the player's sanity.
Insanity: It can trigger sanity events repeatedly depending on your current sanity level (Note: this area doesn't have any callback functions, so if you need to do a complex sanity event use the script area). These sanity events include bugs crawling the screen, flies flying around, and insanity sounds. Check “redist > misc > main_sanity_events.cfg” for more information.
Ladder: This area defines where a ladder is (Note: This is not the actual ladder players will see in the game, but just the area that lets them climb. Make sure you add a ladder model or the players will be climbing on air. Also make sure to keep the area a bit away from the ladder's model otherwise it won't work).
Liquid: This area defines where water is (Note: Just like the ladder this doesn't have the actual water effect associated with it).
Sticky: A sticky area is used to make entities “stick”. When an entity is in contact with the area, it will automatically snap to the center of the area. There are several options for tweaking the behavior.