Holy fucking shit, a game released today has significantly better graphics than a 22 year old game.
Stop the presses!
He was comparing the transition from SMB3:
to SM world:
To the transition from New Super Mario Bros:
to NSMBU:
The gif you posted showed (other than the really obvious features of Mario like the ground, blocks, coins and Mario himself):
Blocks that widen themselves. Featured in Super Mario World.
Fuzzies. Featured in Super Mario World.
Big coins. Featured in Super Mario World (as yoshi coins).
Blocks that appear when you tap the Wii U pad controller. Fucking wow. What an innovative new feature that adds new difficulty to the game, and totally isn't just a tool for parents to help their inexperienced children complete it.
And the picture you selected shows the mountains in the background, a warp pipe, bad guys, clouds, Mario and the floor. The only thing it had that the Super Mario World screenshot didn't have was a tree in the background, otherwise it was just like a HD version of a 22 year old game.
Super Mario World added tonnes of new additions like yoshis, flying (adding loads of vertical bits), new enemies, new blocks that significantly changed gameplay, completely overhauled the graphics (both foreground and background), moved the HUD over the main game and stopped the "lottery" system in favour of the system used in every single Mario game since, made a much better world map, tweaked up the physics etc.
NSMBU changed the numbers to look more tacky like the N64 era, swapped the coins and big coins round on the HUD, changed the little icons, made them opaque instead of translucent so now they interfere with gameplay more, continue to use prerendered models that now just look shiny, made full backgrounds and made the textures HD. They made a couple of things to make the game easier for young children and made it HD, and added a couple of extra features that don't massively influence how the levels are designed etc.
Obviously that deduction is purely from trailers, so I can't really argue how much the gameplay will be changed, but from footage it looks like "more of the same" rather than a revolution.