When clicking the link given in the Beta acceptation mail, I get this : Error for Synthetics Public Beta Walkthrough - Album on Imgur
Interesting, the link works for me, including in incognito mode. To confirm, it looks like you are also going to Synthetics Public Beta Walkthrough.mov - Google Drive right?
Yes, you're right, it's this link. When I tried on my phone, I got a more detailed error : Error on phone. This can be translated to "Unable to play the video. The number of allowed playbacks has been exceeded. Try later.". I'm in France, but even with a VPN to the US, I cannot play the video.