I had this random idea with dolphins but it didn't go anywhere in the final version. I didn't like the rope tileset so I merged it and the grassland tilesets together, nothing interesting behind that.
When I picked the music it had variations for bonus and death routes so I deiced to make harder version of the level after getting all dragon coins, which leads to the secret exit.
Originally I wanted to make secret exit overl-y complicated but thankfully I realized it was just idiotic(you'd have to run from the beginning to the end of the level few times and then finally speedrun it through against p-switch's timer) so I went the so-called death route instead.
So nothing fancy, I wanted it to feel like SMW level to some degree so I didn't go too crazy with palettes or tileset mixing.