Thanks for writing this nice review!

For RetroPie you can instead of the game controller also use the keyboard, just press and hold a key to map it. (it wont show the emulators until you have added the roms of the games in the Retropie rom folders, but you should be able to play the Doom, Quake and Duke Nukem and a few other games.)

Some of the SteemPi features do still require a bit of command line to start them / and configure.
Step by step getting there.

Upped and resteemed, Thanks for testing :) and thanks for getting in touch in the SteemPi Discord server and providing feedback.