The premise / concept for the game was very creative and original!
The gun really hit the theme well!
I can tell a lot of work went into the idea :)
A few minor comments:
The main issue I think, is the exact same one we had, the scale / scope of the game was a little too large for a jam, but I think if you guys carried on dev and polished things up, the game could actually be really good! :D
From just playing I couldn't really figure out how to gun worked (i pieced it together from the screenshots you have on here), but when I did, I was pretty impressed by the mechanics behind it (scratching the disk and firing it was really cool :D).
Although I couldn't manage to get it to fire reliably (i.e scratching / touching the disk wouldn't always let me fire), but maybe that's just me!
EDIT: After watching the video on the game page, I learned how to use it properly!
The locomotion movement + its speed, was pretty bad for motion sickness, again if you toned down the scale of the game (i.e indoor / smaller map) this wouldn't have been so bad.
p.s teleportation was on the controller mapping but I couldn't get it to work? (Oculus Rift / SteamVR)
Overall, under the constraints of a jam, you guys did a good job!
I hope my feedback is useful :)