This page is for the 2008 reboot. For the original, see Prince of Persia.
HKEY_CURRENT_USER\Software\Ubisoft\Prince of Persia\1.0\Engine\
Opening the Steam overlay in the retail game causes all input (keyboard or controller) to be ignored, requiring a restart of the game.
The game will fail to launch while the Steam Controller is connected to your computer. This also means the controller isn't compatible with the game. Possibly related to the Steam Overlay not being supported.
%USERPROFILE%\Documents\My Mods\SpecialK\Profiles\Prince of Persia.exe\SpecialK.ini
Open launcher and lower anti-aliasing setting.