Sonic CD Classic is a classic platformer that follows the adventures of Sonic the Hedgehog as he travels through different areas, collects rings, and defeats enemies to save the world. To start playing Sonic CD Classic you need to select the platform you want and get the game from the respective app store. Then after launching it you will see the main menu, from here you can choose to start a new game, load a saved game, or access the game's options. When you start a new game you will be taken to the first area, called "Palmtree Panic". Your goal in each area is to get to the end by running, jumping and spinning your way over various obstacles and enemies. You also need to collect rings, which are both a form of currency and a way to protect yourself from harm. If you are hit by an enemy without any rings, you will lose a life.

As you progress through the game, you will come across different power-ups that can help you in your quest. For example, speed shoes can increase your running speed, while the invulnerability ability can make you temporarily invulnerable to enemy attacks. You will also encounter different types of enemies with varying levels of difficulty.

One of the unique features of Sonic CD Classic is the ability to travel through time. Each area has a past, present and future version that you can access by finding and breaking time stones that are hidden throughout the level. Future versions of areas are usually utopian and filled with tougher enemies, so it's important to try to change the future by destroying robots that wreak havoc in the past. To complete each area, you need to defeat the final boss. Bosses are usually huge robots that require a specific strategy to defeat. Once you have defeated the boss, you will be transported to the next area and the process starts all over again.