I decided to try to get the gamepad to work in TP VR as it does in Serious Sam Fusion.
And I succeeded, or about 80% succeeded. The game is playable to a point. You can move around, pick up objects, and solve the puzzles, but if you try to interact with a screen, you can't. I was hoping to find a console command that enables look to highlight something you can activate, so if you look at a button you can press A and the game will press it, but haven't found it yet. There seems to be a lot of commands to try out so I am hopeful.
I tried many commands to get this far, but I believe the one which activated the xbox controller was: VR_bVRControllerExclusiveInput = 0
If anyone else who owns the game too can have a go maybe we can fix the screens and get this 100% playable without motion controls.