Hidden Island 12 shares Blizzard Peaks' design. It is a frozen island covered entirely in snow, and is surrounded by icebergs and icy peaks. The island has many (rather sharp) snowcapped black-stoned mountains whose upper peaks breach the white clouds obscuring the blue sky. Along the mountainsides, pure and often colorful ice structures form winding roads, paths, icicles, crystal clusters, symmetric blue ice pillars and spiky ice formations resembling pine trees.
Like most other Hidden Islands, Hidden Island 12 is a short stage which can be finished in less than a minute. For the entire stage, the player will be riding a snowboard. Hidden Island 12 is also quite difficult due to the enemies and bottomless pits which require the player to make precise and slow-downed jumps to pass them.
At the beginning, the player will come to three columns which must be jumped across to reach the upper path. The spaces between these columns each has a solid bottom with a Spring, so the player is not in danger should they fall down there. After crossing the columns, the player has to cross a series of platforms over a bottomless pit. The player will then come to three more pillars which must be jumped across to reach the Treasure Chest. However, these three columns each have a bottomless pit between them.