Thank you for your kind words. My process was to first grab all game code and assets from the PICO-8 using command line exports from the PICO-8 dev kit. Then, since both PICO-8 and Playdate can use Lua, I polyfilled all functions used in the game in PICO-8 to work similarly on the Playdate. But this turned out to be terribly slow (around 5 FPS) and not very legible (not everything looked good straigtaway in 1-bit). So then I started the slow process of optimizing things part by part, both in code and graphism. Most of the time, this meant replacing things draw frame by frame in PICO-8 by using Sprites in the Playdate SDK. You can go through the commit history on Github of how it went (https://github.com/hteumeuleu/celeste/commits/main?after=dd20c9898cbac5b25a40aa8...).