Does the game difficulty matter for any types of run, or can I just run easy?

Basically what the title says, I'm planning on trying to start running all of chapter 2, but I don't know if I'm supposed to start timing when I type the code into continue, or when I actually enter the first Lvl. Anyone know?

For a run to be verified, how much proof is needed? Ive seen submissions which are just pictures of the splits, but that seems easily fakeable, so is there a requirement