I'm a doctor, not a mechanic
From Unreal Wiki, The Unreal Engine Documentation Site
(also see Actor (UT)/Advanced)
 Game-specific Properties
- bool bCanTeleport
- This actor can be teleported. This property must be True for Teleporters to notice the actor.
- bool bHidden
- Specifies, whether the actor is invisible in the game. This property has no effect in the editor.
- bool bNoDelete (const)
- Specifies, that the actor can't be spawned or destroyed during the game.
- bool bHighDetail
- The actor only shows up in high or super high detail mode.
- bool bSuperHighDetail
- The actor only shows up in super high detail mode.
- bool bGameRelevant
- Mutators will not receive CheckReplacement and AlwaysKeep calls for the actor if this property is True.
- bool bShouldBaseAtStartup
- The actor tries to find another actor for its Base (see Legacy:Actor/Properties) at level startup if its Physics property is set to either PHYS_None or PHYS_Rotating.
- bool bStasis
- In standalone (i.e. single player, e.g. Instant Action) games this actor should be turned off if it's not in a recently rendered zone. It will only be turned off when its Physics mode is PHYS_None or PHYS_Rotating. (see Legacy:Actor/Movement and PhysicsType)
- bool bNetNotify
- The actor wishes to be notified of replication events. The actor gets the simulated function PostNetReceive() called whenever replication occurs, e.g. in Ammunition whenever AmmoAmount gets changed.
- float Lifespan
- Specifies how long the actor will exist. This value is constantly decreased and the actor will be destroyed when it reaches 0. In this case the actor's Expired method is executed. An initial LifeSpan of 0 or explicitely setting the LifeSpan to 0 from UnrealScript disables the actor's "destruction timer". Setting it to a value greater 0 from UnrealScript enables it and the Actor will be destroyed after that time unless LifeSpan is set to 0 again before it expired.
 Editor-specific Properties
- bool bCollideWhenPlacing
- The actor will collide with world geometry when placed.
- bool bDirectional
- Whether the editor should display an arrow to show the actor's current rotation. This has no effect in the game. The rotation is set in Movement -> Rotation, or by using the Brush Rotate tool on the actor.
- bool bEdShouldSnap
- Snap to grid in the editor.
TIP: If you add powerups to the map, make sure you go into the default properties (not individual properties!!!) of the designated actor, mark that true, place all you want, and then, mark that false. It will align the ammo or the pickup base to grid and make your map be more like eye-candy (heck, ALL maps are eye candy! ;))
- bool bHiddenEd
- The actor is hidden in the editor. This has no effect in the game.
- bool bHiddenEdGroup
- The actor is hidden in the Group Browser. This has no effect in the editor viewports or in the game.
- bool bLockLocation
- Prevent the actor from being moved in the editor.
- bool bMovable
- Actor can be moved. When false, location can't be changed in-game. This doesn't count for the editor.