Try disabling cloud save and deleting the following folder.

...\Program Files (x86)\Steam\userdata\[some number]\210770\


FPS
C:\Users\Documents\My Games\Sanctum2\SanctumGame\Config\SanctumEngine

Find and change to what I need.
bSmoothFrameRate=TRUE
MinSmoothedFrameRate=22
MaxSmoothedFrameRate=62