You'd have to drastically change the gameplay for a while, otherwise it's going to be a long 40 years before you get going again.
I said above. The signal is sent right after the victory and Aquatoids start attacking within weeks.
In the original storyline, X-Com was put on hold at some point and revived out of a sudden need in 2040. I'd guess that there was a time after the first war in which X-Com became a rapidly expanding international military service which could help explain where Barracuda technology comes from, and why X-Com already had an underwater base before the attacks began.
The manual says that X-COM was shoved aside and ended up becoming a salvage company searching for elerium in underwater UFO wrecks.
If you wanted to feature that story in a game, it might make more sense to be a political strategy game similar to the Caesar series in which you gradually expand through keeping your people happy and appeasing other people, and you generate wealth through economic success and trade. Maybe you'd have the explicit goal of world peace while your major duties involve keeping positive ties with major nations and using those positive ties to gain access to goods and tools that can help you appease the other nations. You'd perhaps explore applications of alien technology to help people while also trying to prevent other nations from abusing it. Various nations would fight over the remaining elerium and you'd try to keep the peace, but in your economically weak position your best bet is probably to design the technology to enable spaceflight to Mars without using it, so that the Elerium mines can be started before everybody blows each other sky high over an infantile resource grab.
No time for that — underwater aliens are attacking! There may be funding drop between the victory and first attacks.
Although, now that you mentioned it, I wonder if anybody tried implementing X-COM clone on Caesaria engine. There were rumours of stranger things back in 2000s
https://openxcom.org/forum/index.php/topic,3025.0.html
https://openxcom.org/forum/index.php/topic,1851.0.html
https://openxcom.org/forum/index.php/topic,372.0.html
Thanks.
By arc, i mean in both games you start with a single base with only meager facilities, a handful of untrained rookies, a minimal science and engineering staff, no access to armour or advanced equipment, and all the funding nations supporting you.
generally speaking by the end of the game, none of these will still hold true.
Correct, this would be a game with lots of trained people (which may change if funding is cut), many research and production facilities, but weapons and equipment inadequate for underwater missions.
they are for all intents and purposes, the same game with a different name.
Hence the desire to combine them
but that's just the structure of the game, the governing rules add a whole other layer of dichotomy,
Then some rules need to change
The sum game needs to combine them somehow.
for example:
UFO only allows bases on land, TFTD only allows them at sea.
I never really understood why do they need deep underwater bases if their subs can fly. Let them be only on land, for example.
UFOs shot down over the ocean in UFO disappear, USOs in TFTD disallow engagement over land.
Let UFOs downed in water stay there a few days, until they disappear, like any other downed UFO. Another thing that irked me from the start
The regions that govern scoring and the country borders are completely different between the two games.
Since the second part follows right after the first, the countries are the same. Let each founding country have a big piece of sea as its territory. Guess, that would affect the 1st half of the game somewhat.
If the spheres of influence over the seas follow current political situation, that would give USA a lot of sea territories, wouldn't it?
The waypoint areas for UFOs and USOs are in completely different parts of the globe.
Is there a limit on numbers of waypoints? Can those sets coexist for different missions?
To sum it up: there is more work than I anticipated, namely reworking the globe. But people wanted this game right from the start. I'm going to find if anybody actually went beyond suggestions...