Yes you can! To play in VR outside of Oculus Home, follow these instructions:

  1. Start the Oculus app on your computer
  2. Select the gear icon on the upper right to open Settings
  3. Select General on the left
  4. Locate the Unknown Sources section and select the toggle to enable this feature

After you have done that, simply launch ADR1FT from Steam and put on your Oculus Rift headset.  The game will automatically switch to VR mode!