For some reason, I couldn't get this working even after trying to run the Unity scene on the correct version and all, but at least the exe in that same github clone started up in the headset. I couldn't interact with anything (I'm using an Index for what it's worth, but I would think that it shouldn't matter much with SteamVR), although looking around with the music playing for a minute or two was still an enjoyable experience on its own.
VR is a magical thing, and I'm glad to see that people have already made a handful of Touhou experiences, so I'm looking forward to the post-jam build of this while I try out the others from older jams! Especially since it seems like you have a few things planned for this.