The developer is using the editor to create a full-fledged game.
Have a look at this impressive level editor made by Game Developer Zachary Snyder entirely on Playdate, a small handheld video game console developed by Panic and released earlier this year. Written in the Lua programming language, the editor allows its creator to set up pixelized game worlds using a wide variety of blocks. According to the developer, the editor is currently being used to create a full-fledged game for the console.
In case you missed it, back in early May, Lionel Lemarié also managed to push Playdate to its limit by making ray tracing work on the device.