The troll fight in the first GOW demo had him using the big rock thing to smash the ice they were fighting on. Eventually the whole floor breaks of an that area is destroyed. That sequence does not exist in the final game. That is fact. Perhaps it existed in some build early on which may have been playable but not in the final one. Sony first party games do this a lot. TLOU 1 did the same. Buddy AI pathing in the final game was no where near as good as the E3 demo. Stuff gets taken out as game comes to completion. Same will happen here.
That doesn't make it fake tho, just not in the final game because games are in development and design and script decisions are made. God of War has way more complicated things than what we saw in that demo.
I agree that there were some things about the TLOU demo that didn't end up being in the game and were important, fortunately for me I didn't notice it when I played it.