If you're writing a fanfic base on a game, you can write it tricky for instance turning some game features into the world of story, like some examples:
In this world, whatever pro pilot you are, you need to pay(or gamble) with the committee to get a mobile suit, which may result in getting useless, crappy, average, good, or hax suits.
- Various missions
Outside of Gundam Fight between people, there's other places on Earth that committee or normal people requesting for help from the mobile suit pilot, where you can write some of the mission in into an actual event that happens in your world. (SCREW the Gundam history timeline LOL)
- Various operator
Just like there's people trained to be ms pilot, there's also other who trained to be excellent operator, you can take their special abilities in game to make them into unique character into the story.
(For example, Operator that give more exp in game could be turned into a character with good combat knowledge that he/she gives good advice to pilot during battle, hence "increase the exp
- Game Mode
Battleship battle, the 10 points limit in game could be turned to such situation:
A team of 4 may only able to send out 2 people/units fighting their enemy with 4 people/units, simply because their suit is more advance, while enemy's may be just average suits
Or Point Match battle, where more than 2 teams or maybe even hundred of units are all fighting a god damn war-like-battle, you could be killed right in the instant without knowing who the killer is, and they just keep coming
Death Match battle...where pilot signed up the battle knowing they could be killed, and the law here is killing is legit, anyone who tried to avenge fallen comrade will be chased down and persecute by law (blood-thirst or insane manic type of character can probably go here as they enjoy it XD)
- Mixing Plan
Well, you could take all those "re-customized" or "re-written OS" stuff here, and make up a few "made-up" Mix Plan, and the results are those fan-made Gundam/units we made up.
...I can't think of anything else by this point, and I think I have said enough
I just wanna say that by adding some (not all, hell no) of these may makes any reader that played this game (SDGO) feels like it's familiar, like they can place themselves into the story, an actual world
I'm sorry if this list of opinions offended you in any way, because as a writer too I know sometimes it can be frustrating that "reader is providing too many opinions"
that I/you just wanna say "Why don't you just write your own damned novel then!?"
lol (thing is, I am already tight on the novel I'm working on, so there's no way for me to get time to write a SDGO one