All these features make me anxious thinking of the amount of work they need :) mostly testing, that is.
But it's nice to see you are so dedicated.
- Question about "game rules": do you actually mean map rules? Because game rules are customizable by the player, and I think you want map-specific uncustomizable rules.
- Game rules / can't respawn: you mean essentially making a "last man standing" mode?
- Game rules / max bots: I'd rather not force such limits. Isn't it better to have it in the map name like others do? E.g. "My map [max 8 players]".
- Game rules / gravity: I may add it I guess, along with the "jump speed" which has been requested again. I still don't think it's a good idea though.
- Properties / can't respawn: you mean objects that are only for the first player to reach them? Or objects that can be taken only once per player?