Virtual Battleground doesn't have a crouch button when in standing mode but does have a crouch button while in seated mode. I hope they change that. 

>>287942876
It's game and engine dependant, many games allow you to use oculus mode instead of steamvr mode but they have various different startup commands. You'll need to research for the specific title you want to use without steamVR. [spoiler]Death to steamVR btw[/spoiler].