Here is a retro gaming device that is tiny enough to easily fit in your pocket. The PocketStar comes with WiFi and Bluetooth connectivity and supports multiplayer games. It is Arduino compatible and open source. It is powered by an ESP32-C3 processor with a OLED display, built-in speaker, accelerometer, and vibration motor.
The PocketStar comes with game emulators for playing Game Boy and Sega Master System Games. It lets you pause games and put the device in standby mode. It will have an app for downloading further games.