The general obsession is just that it was the game that came with the Nintendo 64, so everyone who owned an N64 has played it, so there's a lot of nostalgia to

The general obsession is just that it was the game that came with the Nintendo 64, so everyone who owned an N64 has played it, so there's a lot of nostalgia to go around. The secondary obsession, particular to the speedgame community, is that it's one of the first games to have a formalized, worldwide competitive speedrunning scene develop around it; and there's a shocking level of depth-of-mastery to the SM64 speedgame (i.e. people have been trying to beat the game faster for years, and they're still discovering new ways of doing that.) For the rom-hacking community (to which the game reverse-engineering community is closely associated), I'd say it's a combination of two factors: 1. SM64 has received very little love from Nintendo since its release—many people were anticipating that Nintendo's (temporary) Switch port of the game would at least be modified to be playable in widescreen, but it wasn't. So the community has taken it upon itself to implement the QoL fixes that Nintendo doesn't seem willing to give them. 2. SM64 has many underutilized engine elements, similar to SMB3 or SMW; like those games, it's ripe for modding and further exploration. (It might be said that Nintendo "leaves a lot of level design opportunities on the table" with each of their games.) Games like SMB3 and SMW, which are easy enough to mod, have had heavily-active modding scenes for decades, with many level editors written, new engine plugins developed, etc. But SM64, and N64 games in general, are harder to mod as compiled objects; you really do have to decompile them to have any hope of doing something new or different with them.