- The player is not subject to gravity.
- The player's z-movement is completely unrestricted (i.e. he/she is allowed to fly above ceilings and below floors). This is the main thing that separates it from standard NOCLIP + FLY.
It doesn't seem necessary to expose this behavior to other actors, since I think that applying +NOINTERACTION is close enough to this effect as far as non-players are concerned (since giving +NOINTERACTION to players has trippy side effects). But don't let that stop you from adding it anyway if I'm wrong or it's easy enough to do.
