You can open a project in C++ to create the structure of a custom game. You put one child to work on blender or pixelart software, and another child to compile variables and functions. If you have more than two children, you can also consider assigning a third to animation and a fourth to creating music and sounds.

Whatever alternative you’re offered, I don’t think it’s worth spending more than $50 on an emulator console. (This is the maximum make sense price for any hardware that can emulate old consoles up to PS3).