I'm reviving this old thread to announce that after over a year and a tremendous amount of effort, the game is now for sale, and there is a free demo available that is a lot more polished than what I posted here back in March 2022.
A while back I changed the name from "Monster Test" to "Realm of the Fallen." It went through several genre changes. It has alternated between being a boomer shooter, a metroidvania, and a rogue-lite. Finally I settled on boomer shooter for various reasons.
It is available for the Meta Quest 2, and there is a PCVR version in testing now but not publicly available (if you are interested in testing the PCVR version please let me know!).