Action specials

Hexen uses a single byte for its linedefs' specials (instead of two in the Doom/Heretic/Strife format) limiting the amount of specials to 255 (0 is no-op). However, these specials have up to five parameters, giving them more flexibility.

ZDoom, derived ports and Vavoom use this map format as well and added several additional ones. It is also planned for the Eternity Engine to use them as well for UDMF maps. This list shows which such special currently exist.

Documentation for them can be found on the ZDoom wiki; though it does not differentiate between specials inherited from Hexen and those added by ZDoom.