HappyLand Adventures is a platform game wherein the main character, a dog, explores the entire setting which is Happyland. As a platform game, all the levels in the game consist of multiple platforms that the player has to jump, walk, or run on. There are various obstacles when completing a mission. These include pits and enemies. When the enemies touch the main character, he loses a life. When all the lives are lost, the game is over. The player has to start from the beginning of each level.
In HappyLand Adventures, a level is completed when a certain number of HappyLand inhabitants are saved. The number of HappyLanders the player needs to save is listed on the screen's upper-right corner. When a level is finished, the next level opens up for exploration. Points are also awarded to anyone playing the game. Killing more enemies gives the player additional points. The player can exceed the number of HappyLanders that can be saved. Saving more Happylanders gives the player the chance to explore bonus levels. This can be accomplished by saving all the HappyLanders that are in the current map. When that is finished, all the enemies become gold coins that the player can collect. Collecting all the gold coins allows the player access to the bonus levels.