How that water heater works?
I had that same video game with keyboard. Purchased because of keyboard. But, unfortunately the cassette which came with the set didn't work and I had to buy new game cassette but those cassettes didn't had any program that uses keyboard.
I remember playing Contra (all levels), Mario (used to change world by pressing A and B) , Duck hunt, Adventure island, etc.
Video game is broken and it's thrown away.