Upside Down is a puzzle platformer that requires the player to navigate a red square character through two dangerous topsy-turvy worlds across 40 levels. In each level, they must collect three gold stars inside rings to proceed to the next level through white, portal-style doorways.
Each level presents the player with multiple problems. They must reach stars that typically exist spread out across both worlds. They must direct the red square carefully to slide, jump, leap and drop between platforms and other structures throughout the two worlds so that they don't miss opportunities to reach the stars and the door. They must also sometimes direct it away from shadow- and solid-colored spikes and switch between worlds often. As a result, the ceiling in one area of the first world turns into the floor that the player uses for the square's movements in the second world. Dangerous spikes in one world become part of wall decoration in the other.
Upside Down helps the player achieve their goals in several ways. The player can quickly shift between worlds with the touch of a button. They can collect keys to unlock doors, block spikes and even create useful ledges. Lastly, in later levels, they can use pulsating, swirling portals to rapidly move the square between areas that they wouldn't be otherwise able to reach.
