I was going to post this hack for the C3 summer 2020, but I didn't have time because I didn't finish the first castle level back then.
I imagined if the original Super Mario World had a sequel, and if Mario met some characters like professor E.Gadd and Bowser Jr. before Luigi's Mansion and Super Mario Sunshine.
Also, this hack has a different story plot, but I still think it is inspired from a Mario animation that I've watched recently. I hope you like it.
The hack features wall-jumping.
I've changed the position of the coins and removed some sprites to not make it very hard.
Modified The sky bonus in the fourth level.
UPDATE 31/07/2020: Fixed some overworld garbage.
UPDATE 10/08/2020: reduced the number of sprites in some levels to reduce slowdown.
Everything here is fine with the notable exception of a serious amount of lag, over a large portion of the game. It makes it very frustrating to play. Please get rid of the lag then resubmit; maybe ask for help on the forums if you can't figure it out on your own.