* ActorExistenceLimbo - HirotakaSuzuoki, who voiced [[Franchise/{{Gundam}} Bright Noah]], died between 2 and The Final; all of Bright's lines in the latter are taken from the first game
* WhatCouldHaveBeen - On Banpresto's official blog, WordOfGod said the team's first choice to round out the ''[[Anime/MobileSuitZetaGundam Zeta Gundam]]'' cast in R was Four Murasame piloting the Psyco Gundam, but because of game balance concerns and a lack of weapons they ultimately went with Amuro and the Dijeh instead.
** {{Macross 7}} was also considered for inclusion in R, but the design team couldn't figure out a way to make the "attack with music" system work in ''A.C.E.''. They ended up replacing it with ''MacrossFrontier'', which caused the game to be delayed about a year while they changed things around.
** In one of his blog posts, Terada mentioned that {{Super Robot|Genre}}s aren't normally supposed to get into ''A.C.E.'', but some factors could change that[[note]]Specifically mentioned are popularity and ability to mesh with a 90s[=/=]2000s-style serious plotline[[/note]], and listed a bunch of shows that were considered but ultimately rejected. This list includes: ''{{Daitarn 3}}'', [[{{Braiger}} the J9 Trilogy]], ''ShippuIronLeaguer'', ''JushinLiger'', ''{{Daiohja}}'', ''{{Zambot 3}}'', ''SpaceWarriorBaldios'', ''Anime/TriderG7'', ''MakyouDensetsuAcrobunch'', ''MiraiRoboDaltanious'', the Eldran franchise, ''{{Goshogun}}'', the [[CombattlerV Nagahama]] [[VoltesV Romance]] [[{{Daimos}} Triolgy]], ''GoLion'', ''GodMars'', ''{{Gaiking}}'', ''KotetsuJeeg'', ''GEARFighterDendoh'', ''GodSigma'', ''MechanderRobo'', and ''{{Raideen}}''. Also mentioned as prime candidates were ''GaoGaiGar'' and ''NinjaSenshiTobikage''.
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