A few disclaimers: 1) It's common for a game's look to change over the course of development 2) I'd rather have slightly downgraded gfx in exchange for smooth performance 3) Some elements I find to look better with the new build
That aside, there are some very curious changes from the original reveal. I feel as though they added another lighting pass of sorts to add brightness to dim parts of scenes, adding a nice pop to overall visibility. On the other hand, I'm seeing a lot of asset swapping and lower res textures and transparency at work. All consistent with performance tuning, no reason to deny it or call them liars.
Face texture looks lower res, lower quality lighting, and lower quality transparency on hair, eyebrows, eyelashes...
Web looks different, some lower res textures present...
Lighting and transparency on hair changed...
Even the dinnerware and table reflections look different
On the positive side, the lighting change made things more visible, which could aide in gameplay. Also, it helps to show more geometric and texture detail on the buildings.
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I remember something similar with Halo Reach's reveal trailer. It had better assets and lighting in the reveal(since they exported the frames and built a 30fps video instead of capturing real performance), but the dev came out said they improved the overall look. Now, obviously they downgraded the scene and threw on different lighting. It was their opinion that it look better, but it didn't factually change the downgraded elements. Spider-Man looks great, maybe it's just a "Base to Pro" difference, but usually PS4 games don't get a large settings change. Either way, something is different. Actual gameplay impact = little to nothing, maybe positive gains for visibility and frames.