Legendary games developer Shigeru Miyamoto revealed in an exclusive interview with Dragon Quest creator Yuji Horii that he generally creates the first level last when he’s creating action games. Miyamoto also says in the interview, which was from 1989, that his teams reduce the difficulty of his game’s levels by around 20 percent once the game is complete.
“When we’re doing an action game, we make the second level first. We begin making level 1 once everything else is completed.”
“Your first level (or tutorial, or sequence, or whatever you want to call it) should serve as a prologue for the rest of your game. It should introduce many of the concepts your player will be interacting with through the rest of your game, and it should do so in a way that doesn’t alienate them right away.”