Sometimes, games appear very different once they actually release compared to pre-release showings; what in your view are some of the biggest glowups (upgrades) and downgrades in the same game from pre-release to the final product? (Can be both graphics, but also style, vibe, etc)

I'll start; the Switch 2 port of Star Wars Outlaws looked awful and ran like a three-legged tortoise, but the final product was much better and a real showcase for the system.

There's this classic:

Gotta go back 21yrs to ‘05 for when Sony tried showing the CGI rendered trailer of Killzone 2 as actual gameplay.

That's the first one that came to mind for me too.  Jack Tretton straight up lied when asked about it point-blank.  So glad that tool is gone from Sony.  Really didn't like that guy.

Meanwhile for me Star Wars Outlaws demo is what made me abandon my idea of Switch 2 being my primary system for third party lol.

I think Aliens Colonial Marines had a notorious trailer that was much better than the same scenes in the final release.