Two news here. First of all, the Stage library now has support for the PyGamer device, so you can play all the games on it. The analog joystick is translated into button presses.
Second, the official displayio library grew support for partial screen updates, which makes it much faster — sufficiently to replace the Stage library in the future. So far I have ported the bouncing balls demo to it, and I'm working on the remaining games. I also plan to write some tutorials.