Base defense mission is almost implemented (only missing the logic of the aliens trying to destroy the facilities and actually removing the facilities from the base, and a few other details :p).
I'm planning to continue getting all the mission types working, then looking for a general system of "mission rules".
I know, I work backwards :p
But hey, at least I'm still working on openxcom :p Otherwise it would probably be an abandoned project.
To give you an idea what will be possible by changing only rulesets:
- make the ufo alien base attack a two-part mission
- make the tftd alien base attack a one-part mission
- create other terrain types for terror missions, alien bases, UFO's (the system will choose a random terrain type when multiple types are linked to one mission or one UFO)
- change the size of all maps in all missions except base defense (there is no limit to the map sizes or number of objects on a map, but beware the "alien turn" will take some time if you put thousands of aliens on a map :p )
- change the number of aliens in all missions, their ranks and what items they carry
- ...