Use Godot's Tileset Editor to quickly paint classic levels like World 1-1.
If you want to build a playable "piece," you can use modern engines to recreate the NES experience. Super Mario Bros NES
For a deeper technical dive, resources like Harvard's CS50 Intro to Game Development explain the tilemap and animation logic behind the original game. 3. ROM Hacking & Modding Use Godot's Tileset Editor to quickly paint classic