OG noob here. From which SRW games did the OG series derive/adapt their story arcs?
OG1 - ?
OG2 - ?
OG Gaiden - ?
2nd OG - ?
OG1: 2 and a variant of Alpha 1 without its two main villains as the enemies in the second half.
OG2: 3, Alpha Gaiden, A, Impact, Alpha 1's unit upgrades, Arado route of Alpha 2.
OGG: The final stage of 3 (Armageddon), Compact 3, R, some Great Battle stuff with Dark Brain, Scramble Commander.
OG II: EX, 4 (but not F/Final), the other three Alpha 2 routes, early Touma route Alpha 3, D, MX.
Real Robot Regiment didn't really have any plot in OGs2. Ariel and her brother did a grand total of nothing relevant aside from providing an excuse for Alfimi to be missing for most of the game. Dovan didn't even get his final form from RRR.
OGs 2 did attempt to do a really weird (and crappy) iteration of the Super Hero Sakusen plot substituting Ing for Ingram and La Gias for time travel among a number of things.