I know that the Raspberry Pi can do either of these things, but can it do both?
I am aware that there is an OS flavor(?) RetroPie that specializes in retro gaming. But then can it still do other things, like run scratch?
I also understand that Scratch is included with Raspbian. But will there be any issues running the emulator MESEN?
Whichever solution, it should be able to accept game controllers, for use both with MESEN and Scratch - preferably PS4 controllers via Bluetooth (or at least a USB gamepad).