When I made "I wanna be the Pookie" a fan game about a streamer, I didn't know how to make it easy for me to layout different maps. SO I used what i know and made it so I could visualize each of them in a spreadsheet. The game engine interprets a CSV file and renders the map from there.
Overall I recall making this little game an interesting challenge. Since it was created using the P5.JS framework and this was before AI assisted programming really became accessible to me, there was a lot of learning I needed to do.
Luckily the framework is very beginner friendly, and I knew going into the project that it would be a Final Fantasy "I want to be the Guy" ripoff/inspired/influenced game the basic ideas were already in place before I even learned a single thing.
As mentioned above, the map system was going to be a challenge for me to implement, but i first needed to implement the basic movement and gravity. I actually spent quite a bit of time relearning how to make hitboxes register correctly, and had a dev map with a bunch of blocks I'd jump between to make sure I could get things just right. I tried to remember the development of Super Mario 64, in which the developers focused heavily on how movement should feel and be rewarding.
By no means did I come close to capturing a good feeling movement system, but I am happy with the way it ended up.
Back when I posted the game on Itch.io I commented on the world building system, and i really am still proud of myself for integrating it. It was a great way to understand level design. If i were to do this project again I would think more critically about the layout of the levels. I did include some pixel perfect jumps, and the limitation of the block by block system, and the speed an jump/gravity I chose meant the levels were either to easy or too hard. In order to test the levels I actually doubled the values, and then implemented it as a power up in the game.
The final implementation of each level, was mapping it out in Google Sheets, and then copy pasting csv values into an array in a file called "levels" that called the next room based on the player room location and what wall they hit. Nothing groundbreaking but I'm proud of it.