This wasn't made entirely clear so I wanted to ask, can a run be submitted if the player is using stealth camo, infinity face paint and EZ Gun, or are those items prohibited? and is a video absolutely required? thanks in advance to anyone who reads or answers

Hello, I have a question about "single segment" too. I know that it does not allow to "load save". But if I just "continue form game over screen"? thanks

As long as it says 0 saves at the end of the game it is classified as single segment. So you can press continue on the game over screen as many times as you want and it will still be single segment (as long as you still have not saved on that run of course). Multi segment is with 1 or more saves.