OFF Phase 3 runs perfectly under Windows 10. Installed it Months ago and I never had any Problems. Ankor's Shader Mod also works fine with it and gives OFF Up-to-Date Graphics
Please install OFF into a different Folder, NOT into your WOFF-Installation, for Example call your Folder "OFF Phase 3" and install the Game to this Folder.
For Example: D:/Games/OFF Phase3
OFF doesn't overwrite anything from WOFF. Both Games can Co-exist on your Hard-Drive.