Sometimes people just can't agree on what "completing" the game is. E.g. an RPG like Final Fantasy VI where "100%" in terms of speedruns it is just getting all characters and espers, where someone else might consider Strago's blue magic and Gau's rages a part of it.
You don't want to fall down the rabbit hole of what counts as "complete" in Final Fantasy games. I'm doing a perfect run of Final Fantasy 7 since they just released it on PS4 and man the community has some crazy requirements for a perfect game.
You have to do some pretty insane things like creating glitches that force the game to have you fight a boss twice in a row just in order to get 2 copies of whatever, unique, one time only item the boss drops. Or other crazy things like getting 99 copies of a piece of equipment that is only acquired in one specific part of the game and then forever becomes unavailable, forcing you to fight a specific enemy over and over again in order to get it to drop the item or steal it from him until you have 99 copies. You also have to hold on to certain items that the game expects you to use, just so you can boast having a complete inventory. Then there's stat maxing, which in FF7 requires tons of resets in order to get the game to give you the right stat boosts for HP/MP on level up.
Oh, and then there's FF12, where a complete game requires you to get items that enemies have a 5% chance to drop, fighting optional bosses that LITERALLY take hours to defeat and making sure you don't open some random treasure chest early in the game that forever makes a certain unique piece of equipment impossible to ever acquire
And I can't forget FF 9, where you have to do everything in the game under a very strict number of hours, otherwise a certain unique item near the end of the game will not become available to you. Having to do everything in the game under a time limit, is insane.
FF X requires you to win that hard storyline blitzball game and dodge 200 lightning bolts for one character's ultimate weapon and get an insane time in a very poorly designed mini game for another character's weapon
The FF series doesn't get enough credit for just how hardcore it can be