There is no rules that run needs to be short, or your minesweeper PB, so that means I can submit 999 second run?

Please don't.

This site's moderation rules state:

Runs that are clearly not making an effort to beat the game's category quickly may be rejected.

So it doesn't really have to be spelled out in the rules for an obvious "slow run" to get rejected. On the other hand the mods might still accept it since that's just guidance.