Here is another handheld gaming device that lets you play retro games anywhere. The 32blit not only lets you play but develop your own games. It has 24 game programming tutorials and handy tools for editing sprite, map, and sound effect.
The device has a STM32H750 Cortex-M7 processor, 3.5″ 320×240 16-bit IPS TFT display, 0.5W speaker, accelerometer, 1200mAh battery, analog joystick, D-pad, four action buttons, and two system buttons. It introduces you to C++ and Lua coding.