Recently, IGN decided to recall an interview with Shigeru Miyamoto. The developer went through level 1-1 in Super Mario Bros. and commented on some moments.
Miyamoto explained that the "educational nature" of the early stages usually appears after more complex levels have been developed, i.e., they approach their creation with an understanding of what skills the player needs to develop for further passage.
The first level consists of 15 screens (including the underground room), but it feels large, as the landscape changes after 2-3 screens.
At the very beginning of the level, the player is greeted by a Goomba: if he runs into it, he will die and immediately learn a lesson - you need to dodge (jump over).
The block with the "?" sign should interest the player, and after hitting it, he will receive a coin. This will create a desire to break the next block, under which a mushroom is already hidden.
After the impact, the mushroom will fly out and begin to slide towards the pipe, from which it will bounce and fly towards the player. Since blocks are installed above the character at this moment, it is difficult to dodge the mushroom, and when Mario collides with it, the player will understand that such mushrooms are not "enemies", but are a bonus.
By the end of the level, the player will know what he needs to do to complete Super Mario Bros.