Unfortunately these changes aren't helping to implement TFTD sea/artefact mission types either.
+ Island/Port terrors being part of mission zone3 are easily done with -1/-2 types, but I still couldn't find where I can put custom briefing text depending on terrain type.
- Sea terrors and artefact terrors are not related to specific geographic regions per se. Despite they can be initiated by region-related mission type of activity, in fact their coords are taken from the "global" location lists. (In opposite to logic of city/port/island-based terror sites, which are fully region-related).
- Sea terror coord list consists of 48 different unnamed locations, with last 5 USED locations kept in the save (not to repeat same location). Type of terrain - cruize/cargo is chosen randomly, 50/50. I simply failed finding where to put this global location list.
- Artefact terror coord list consists of 36 different unnamed locations, with last 12 locations kept. List is also shared between regions, and have no place in current structure.
- I couldn't find how to make STR_ALIEN_TERROR a kind of an alias, or some META-MISSION type mission with ability to have some inner-distribution, weights through months/waves and references to specific missions. Also there is a need to have ARTEFACT mission spawned only 12 times, and then - ratios of terror missions gotta be changed (artefact is zeroed -> others are filling proportionally).
- Terror types through months:
0,1,2 : 100% port/island attack
3,4,5 : 40% port/island attack, 60% cruize/cargo ship
6, ... : 20% port/island attack, 30% cruize/cargo ship, 50% artefact (after 12 artefact missions spawned it becomes 0%)