Well, my whole plan for Mariovania was a single sheet of paper with map laid out and rough estimate on what item or boss is where and the progression route. I came up with every other detail just when developing it (I usually don't know how the room will look until I make it, a total improvisation), following the plan for room placement and some general idea I had in my head. The Distortion area didn't follow any written plan at all, I just randomly placed rooms as I roughly thought it would make sense. Some of castle stuff wasn't originally planned, but I added few rooms because thought it would be cool.
That being said, it is possible to create a very complex game with minimal planning (or no planning at all). But to prevent you from getting lost, you need proper tools that will do the world indexing for you. E.g. for Mariovania I had a search tool that could look up every single item box on the map when I needed to locate some item.
That being said, it is possible to create a very complex game with minimal planning (or no planning at all). But to prevent you from getting lost, you need proper tools that will do the world indexing for you. E.g. for Mariovania I had a search tool that could look up every single item box on the map when I needed to locate some item.