You've stumbled across a barely functional, wildly incomplete and basically undocumented Rust crate whose aim is to let you write games for the Playdate handheld gaming system in Rust.
This software is not sponsored or supported by Panic.
To use this crate, you'll also need to install the crank command line tool.
From the crankstart directory where you found this README,
crank run --release --example hello_world
Should launch the simulator and load in the hello_world sample.
If you have a device attached to your desktop,
crank run --release --example hello_world --device
Should launch the hello_world sample on the device.
For the sprite_game example one needs to copy the images folder from "PlaydateSDK/C_API/Examples/Sprite Game/Source/images" to "sprite_game_images".