Gaming

I found that in certain missions in gta 3, if you manage to start the mission twice (ie have two instances of the missions running, it's possible by glitching the on mission flag), then you can auto pass the mission by doing something that would normally fail it (like dying).

It's called "dupe and fail" and is used in the speedrun.

I'm credited with the discovery even though someone managed to do it before me. It's just when I did it (on a different mission), we were able to put the pieces together to figure out why it worked and then replicate it. We both found it by accident

For a brief, simple, explanation, it works on missions where the objective is to kill someone or blow something up. When you have two missions running and then fail, the game starts unloading assets for the mission. The other instance of the mission is like "hey, that dude you were supposed to kill got unloaded, mission passed"