Larian visited the Eurogamer office to show me the new and improved Definitive Edition of Divinity: Original Sin 2 last week. To do this the developer ran two versions of the game - old and new - side by side to highlight the differences. On one screen we had DOS2 as it exists now, played on a gaming laptop; and on the other screen we had the Definitive Edition of DOS2 played on an Xbox One X dev kit. The difference was striking.
It wasn't a Digital Foundry-style controlled test, with the laptop fans wheezing and picture coming through an older 1080p screen, but it got the point across. The Xbox One X version, running in 4K resolution and with high dynamic range enabled, was brighter, crisper and more vibrant. It was smoother and more responsive too, and will apparently run native 4K30 on Xbox One X, and dynamic checkerboard 4K30 on PS4 Pro.
The reasons for the differences run deeper than hardware. The physics engine has been changed for the Definitive Edition and numerous improvements have been made, making the game up to four times faster in certain areas. The fire effect, for example - which spreads across a lot of environments a lot of the time - has been changed for one more economical and arguably better looking too. It's a similar story for many of the game's 'surfaces', and textures have been improved as well.