So I launched Revolution for the first time and decided to go with Training aka Demo levels, first of which was Karnak. I played all the way through the level(i was playing on Serious difficulty btw) to the final temple, in which Sam should've placed Gold Amon statue on a pedestal and afterwards faced group of Kleers skeletons in the corridor.

However, the final cutscene was bugged: before Sam walked to the pedestal, the doors which should've opened only after placing the statue opened before that, and then Sam just walked past by, not bothering placing Gold Amon, into the Kleer corridor. And afterwards, before camera flew to the end of corridor to then show group of Kleer skeletons running towards Sam, they started running earlier; funnily enough, if you don't manually skip the cutscene at this moment, one of Kleers will jump on Sam and hurt him, abruptly ending the cutscene anyway. Loading saved game before the cutscene didn't solve the bug.

Out of curiosity, I decided to see if this bug will occur again, and thus started Karnak Demo again(on Normal difficulty), though this time I decided to skip most of the level through rocket-jumping out of the window in the first room and then walk to the final area, just to see the cutscene. The final cutscene was broken again this time.

So, in short: the final cutscene in Karnak Demo is broken. Sam doesn't place the Gold Amon statue on the pedestal, exit doors open anyway, and Kleer skeletons spawn before camera fly across the corridor to its end.