I have a question. Are segmented runs allowed? Or does it all have to be in one sitting?

Segmented runs are not allowed, for fullgame runs on sr.com leaderboards you need a full run in one sitting. However, you could use segmented runs for strategy and guide making, so you can post these here or under Guides, if you think they show something particularly valuable for a fullgame run.

On another topic, I guess missions could be called "individual levels", but I personally would be against making IL leaderboards for them, the reason being that the most optimal way to play them would be from a full save with Power Mode but that kinda brings them down to grinding and luck.

Understandable. Alright, thanks!