I was amazed with the demo as it will give users a whole new experience and excitement in VR technology and I think it will be a part of our daily lives in the near future. 
Hi, thank you for your feedback! You can also try our constructor, which has been announced today!
https://sandbox.mark.space
It's not possible to test the constructor with the guest log-in, isn't it?
Yes, i've tested it some time ago and everything worked flawlessly. Haven't tried it in the last couple of days though.