Above, you can see a mod that upscales textures using AI. Some of the most noticeable changes occur on paintings. There are also significant improvements to the look of trees and doors. CrashCrew are working on the texture improvements shown above.
You can also replace Mario with an HD version of the character. Based on the footage shown off below, the swap appears relatively seamless. Mario will look better than his surroundings, but it isn’t that jarring in the clip. Armando Arredondo is behind the HD Mario mod.