Okay, I completed the level 'Betrayal' and there was a blurb image, and then right to the after level screen. I checked online and found out there was supposed to be a major cut scene afterwards!

I am NOT happy about this!!!

I just played it tonight and the Betrayal cutscene was still missing.

Bug still there.

Just had the same problem. Actually, I started missing the cutscene after the Forever update. I had already played the game once before that and then the cutscene was in place.

Edit: looks like Steam users also have this problem ocasionaly: https://steamcommunity.com/app/488960/discussions/0/1697169163396552894/

I recently played through Star Vikings Forever and had this exact issue on my first playthrough. I am using the linux version of the game. Otherwise, the game plays fine. It was rather strange to have a bunch of things in the game suddenly change and have no idea why.
update: I found a video that has the cutscene, in case anyone wants to see what they missed, though it's from a playthrough of the beta version, so it might not be the same:
https://www.youtube.com/watch?v=afRRZYPFMGM

I ran into the same bug but with the Windows version. For some reason the game is still not playing the Betrayal video.