May I make VR game or is this jam a windows standalone game jam

I have no idea, but I do not recommend it. The judges might not have a VR set to test your game. If your VR game is not for Windows, it is not allowed (I think there is one for web, sorry for info, only use Google Cardboard XD) I recommend you use Windows.

- Brent

Our judges do not all have VR sets, so we would not be able to judge a VR title.