From Polyamoryfuckedmywife interview with Bluepoint games:
“Everything that was in the original PlayStation 3 version is in the standard edition of the game,” Moore said, when asked about new items and equipment coming to Demon’s Souls as part of the game’s digital deluxe edition. “So nobody’s missing out on anything. There’s a lot of new content that we’ve added to the game and for fans to find and enjoy. And there are lots of things that I think fans are going to go, ‘Oh, that’s amazing. Great. You know, I didn’t know they put that in the game.’ I’m not going to tell you any more than that, because [I don’t want] to spoil anything.”
New stuff:
"We know that the remake will have new weapons, armor, and rings,"
Some incline:
"One change that will affect players’ encumbrance — aka how much stuff their character can carry — is how much healing grass they can hold. In the original Demon’s Souls, players could carry hundreds of healing grasses with them and suffer no real penalty. In the remake, players will have a more limited supply, and more powerful grasses (like Full Moon Grass) will weigh more than less effective grasses. Those changes should help balance the game’s difficulty and improve player-versus-player battles, where fans could quickly consume vast amounts of healing items, dragging out multiplayer brawls."
For folks who want colors closer to Playstations 3 version of game:
"“If you like the starkness and the despair of the original PlayStation 3 version, then we have a bunch of filters that you can choose from and play the game [that way],”"
About music decline:
“Unfortunately, the music that was recorded for the original version was digital only,” Moore said. “And I think the score by Shunsuke Kida is so good that to do it real justice on the PlayStation 5, we had to make sure it was recorded by a full orchestra. So we created a modern reimagining of Shunsuke Kida’s amazing score with dramatic new arrangements. We went to AIR Studios in London and we recorded that with a full orchestra [and a] full choir. We even recorded a famous pipe organ in Temple Church in London. And that runs as a theme for the music, giving it this really dark, wonderful, flowing sound. I think there are 120 of the finest musicians in the world on this score. It’s stunning. I think people are just gonna love the way the music sounds.”
About voice acting:
"And just as the music has been recorded, so has the game’s dialogue. There’s good news on the front: “We approached the original cast and asked them to come back and take on their incredible, iconic roles,” Moore said. “And we were very lucky to get many of those [people] back. Obviously, some people, their voices changed or they moved on from acting, but we did get many of them back. And we re-recorded all the new dialogue. That was an incredible experience for us.”