Try as I might, I don't think I can have an update finished before this month is over, so I should probably continue telling people things they can figure out on their own about the game to instill some life on this webpage. Today on the slate: GGG variants you can run from the box.
While writing up the rules for GGG, I knew that I wanted a system that could be adapted to most styles of Mecha without much (or any) homebrewing being obligatory, possibly one that would not be an unreasonable pick for games without remaining strictly in the realm of robots. All you really need is a concept for a game where there is a clear distinction between the character proper and their "combat form". Examples include:
Medabot-esque mecha pet combat is so obvious in hindsight that it is kind of cheating. This actually surprised me at first, but it fits like a glove and in some aspects makes better use of GGG than regular mecha. No homebrewing is necessary to run this beyond replacing ejection mechanics for simply being defeated and removing assimilation weaponry entirely - it just does not fit the tone. This could be extended to the rest of the 'monster trainer' genre with some creative refluffing, mostly in the weapons department.
Powered armor, Tokusatsu and Sentai (Power Rangers and their ilk, for those unfamiliar with the term) are the coming in second. It is perhaps the most obvious of the variants, being a close sibling of Mecha since the dawn of the Genre. You can run it without modifying the rules at all save for downplaying the brutality of Maiming and replacing Ejection with transforming back to normal forcefully or some such.
The third runner ups are starship battles, another one that I did not think of until it was brought to my attention. While you are not going to be a full-fledged fleet commander like the admirals in Legend of the Galactic Heroes, you totally can replace robots with starships and call it a day. All you have to deal with are the ejection mechanics (you can abandon ship at any time leaving a trusted officer behind, perhaps you have a limited number of those, or you can only do so if they are an Ally or better) and the fact that melee weapons and their related mechanics are pretty terrible ideas in-character unless you are a bunch of space pirates or similar. If you go this route, you may want to replace Duels with a "boarding party" mechanic that damages Grit directly while you are engaged or initiating an engagement.
Once your gears start turning, you can start to work from this base towards more esoteric things. My favorite variant so far, and one I did think of before a prospective GM came to me with, is that of using GGG to run a game akin to the Persona series of Shin Megami Tensei fame. As an acquaintance put it: "They summon robots to fight". Themes can substitute or be expanded to handle Social Links, Weapon types can do the same for Elements and you can even make a super special unique snowflake Fool Arcana type thanks to Transform and Mid-Scene Upgrades that give you further Transformations, without being imbalanced when compared to the rest of the party.