Front Defense VR, by Fantahorn Studio, is finally available, but you can only get it on Viveport at the moment. A Steam version of the game is not available right now. You can purchase the game outright for $19.99, or get the game free, via the Viveport subscription (assuming you still have a slot left). One word of caution about Viveport, while the service sounds extremely promising, users have complained that the software once installed onto their computers has given them issues. The software is known to be somewhat buggy, and something of a resource hog. Still, others have reported that Viveport has run perfectly smooth on their systems, and that they haven't had any problems whatsoever.