The Sonic games always start out easy enough, but they ramp up in difficulty pretty quickly, and I usually peter out after about four or five Zones.
But what if you want to see the rest of the game without working for it? Easy!
First, go to the Options screen.
Then play the sounds in the Sound Test in this order: 19, 65, 09, 17.
Then hold C and press Start to go back to the title screen, and once there hold A and press Start. The result?
A menu that lets you decide where you want to start the game!
Which is very handy if you're lazy (like me).