Introversion Software has put up a new version of their prison building simulator, Prison Architect, bringing the game up to version Alpha 15 and adding modding support so players can create their own modifications for the game.
In addition to the modding support, Alpha 15 adds a massive swathe of optimization improvements to the game that the developers brag about (and rightfully so!) in their latest video announcing the game's update, which you can see below. The optimizations allow players to massively improve the size of their prisons without experiencing slowdowns on their computers.
Prison Architect has been on sale over the weekend for $15 on Steam. If you didn't grab it then, there's always the Christmas sales.