Levels / Level Objects
A level may contain a wide range of objects specified by the level designer. Here are the fifteen different types of level objects that may be added to a level:

Player Start Locations
Ammo Packs
Animated Scenery
Lighting Effects
Force Fields
Hot Zones
Message Panes
Respawn Locations

During the course of a level, certain types of objects may be added or removed from the level. For example, a dying character could drop an ammo pack, or the act of walking into a hot zone could trigger a routine that could cause a new character to appear. Naturally, when the player collects an ammo pack it is removed from the level. But not every type of object can be added or removed while a game is in progress: player start locations, animated scenery objects, lighting effects, doors, switches, force fields, hot zones, message panes, and respawn locations all exist in fixed quantities.

Information on creating and editing level objects is available in the Adding Level Objects and Level Object Manipulation sections.