"Any card—so long as it exists—has a power that is needed."

After some Remaster Googling, found this link with screenshots and comments about episode 1! (Note: most suffer from jpg-compression syndrome)

So, from the looks of it, the footage gets cropped top-and-bottom with nothing added to the sides to make up for it (like in DBZ Kai). Also, reading some of the comments, it seems Shunsuke Kazama might’ve re-recorded his lines for Yugi and Dark Yugi? One mentions Dark Yugi not sounding as monotone as he did before.

The bigger things, though, are probably the OP/EN edits.  Aside from “20th Remaster” added to the logo in the beginning, shots from the episodes replace those shots of Jou/Honda/Anzu in VOICE, as well as some scenes of Pegasus and Yugi added over the ending verse, and the Pegasus still/Yugi and co stareback seems moved to fit into the last line in the song. Meanwhile, An Energy Shower/Genki gets a pretty big overhaul; instead of just the puzzle box with different pictures in it, we now have the puzzle box in the background with shots from early Duelist Kingdom on top of it, starting with Yugi solving the puzzle and Jou/Honda teasing him.

No raw to watch this all in motion yet, from the looks of it, but I feel like the cropping could’ve been done better, at least.

Also, what’s a remaster without some QUALITY still sticking around?