You control Mr. Yo-Yo. You are given five lives at the start of the game – one in play, and another four in reserve. The object of the game is to descend to the bottom of the cave, and rescue the Notelies by returning them to the top of the cave. When a Notely is ready to be rescued, he will appear in the little bucket area at the bottom of the cave. To pick up the Notely, descend to the bottom of your string. Mr. Yo-Yo will begin flashing various colors to indicate you’ve picked up a Notely. Then, return to the top of the screen to release the Notely to freedom! Mr. Yo-Yo will then return to his normal color, and you can get ready to rescue the next Notely. Sometimes, you may have to shoot some enemies to get the Notelies to appear. The further you get into a level of caves, the more timid the Notelies become. You’ll have to shoot more and more enemies for them to have enough courage to appear.

There are five different types of creatures inside the caves (Blobs, Flappers, Bouncers, Stunners, and Snippers). If Mr. Yo-Yo comes in contact with any of them, he’ll lose a life. Some of these creatures may also interact with Mr. Yo-Yo’s string in various ways. So be sure to keep an eye out above you if you’re spending a lot of time at the bottom of one of the caves!

You'll find various objects in the caves that can help you out. Coins, which you can collect or shoot. Power Pods, which you can also collect or shoot, but it's better to collect them (just as with the coins). However, shooting a Power Pod will clear the screen of enemies! Bonus Targets fly around in Bonus Caves -- shooting ten of them will cause the Bonus Gem to appear. Collect the Bonus Gem and bring it to the top of the cave before the time expires for a large point bonus and extra life!

The game ends when you have lost all your lives.