The biggest downside to having Shared as the default is that this requires a subtractive security level system. You start with Shared (all levels) and subtract those levels that you don't want down to Staff only. I don't think this is intuitive. Instead, starting with Staff only and adding levels up...

In the current system you can pick a security level for a room from the list Shared, Min Sec, Med Sec, Max Sec, Protected, SuperMax and Staff. But with all these security levels, I would like to be able to mix them. For example, my main canteen is off-limits to SuperMax prisoners, but there's no way...

Currently the game considers a wall a border on one or the other side of the wall. Instead, the game should consider the middle of the wall a border. This would instantly solve all those problems with inaccessible areas, doors and walls not being placed or demolished, and room designations that run ...