You can use the arrow keys and Z and X for A and B. If you want to make your own games, you can use the template and if it's cool, I might add it to the Simulator as a cartridge you can play Template VVV https://scratch.mit.edu/projects/1362934723/
Took about a couple of days to make. Note: if you make your own game in the template, it WILL say that it is best to condense the game into 1 sprite but if you don't want to that is fine. If I add it to the game, I can do that part myself. Also, I might change the colors a little to match the color pallet for this simulator.