Hard to say exactly because it was spread out over a few months. It was about 6 months from the start date to the final upload on Itch, but I was probably only working on it for an hour or two each week. Also I came back to it and added Caffeinated Mode (the time limited mode) a couple of months after I first uploaded it. Full-time it probably would have taken a week. Pico-8 is a very fast development environment, particularly with Aseprite and the VSCode Lua & Pico-8 plugins.