One of the first things that may stand out to you about the Playdate version versus the Game Boy version is the size: Playdate’s screen has a 400x240 resolution, versus the Game Boy’s 160x144. If you’ve done any development for old systems, or if you’ve designed retro-style pixel art games, this resolution may at first feel like it gives you a huge canvas to work with, but it’s important to keep things in perspective. Even though Playdate’s resolution is really high, the display’s physical size is somewhat comparable to the Game Boy, meaning the device has a high pixels-per-inch ratio. In fact, even though Playdate’s display is wider than the Game Boy’s, and slightly larger across the diagonal, it’s actually a little shorter vertically.
Excellent write up on designing assets for a Playdate.
https://chanc.ee/20211213-playdate-art-scale.html