You need to upload a legitimate Sonic 2 ROM (The File is called SONIC2_W.68K)
You can get this by pressing the Download ROM button, and then choosing it with the Choose File Button
After that, it should just start
Controls:
D-Pad = Arrow Keys
A,B,C = A,S,D
START = ENTER
You can get this by pressing the Download ROM button, and then choosing it with the Choose File Button
After that, it should just start
Controls:
D-Pad = Arrow Keys
A,B,C = A,S,D
START = ENTER