While Mario Kart 8 Deluxe is overall a clear improvement upon Mario Kart 8 due to the addition of large amounts of extra content, there is one small detail that was lost in the remake compared to the original.
Top: the minimaps for the Grand Prix tracks (seen in the bottom right) are usually blue in Mario Kart 8 on the Wii U, but the minimaps for the three Rainbow Road tracks are actually rainbow-colored as an Easter egg.
Bottom: in Mario Kart 8 Deluxe, every minimap was recolored to grey, removing the rainbow coloration Easter egg entirely.
Main Blog | Twitter | Patreon | Small Findings | Source: 1, 2
In Mario Kart 8 Deluxe, a glitch can occur with Link's animations when viewing a replay of a race. If Link uses an item immediately before or after performing a Jump Boost, his item throwing animation in the replay will interfere with the Jump Boost animation (posing with the Master Sword).
This will result in the glitch seen in the footage, where Link's arms and sword will not render properly, causing his sword to appear to float in mid-air.
Main Blog | Twitter | Patreon | Small Findings | Source: youtube.com user "Mankalor"