Hidden Island 7 shares Plant Kingdom's design. The island is a blue-skied untamed jungle with enormous plants like leaves, flowers, plant stems and fungi everywhere. All around are enormous undergrowths like moss stalks and flat fungi stretching into the sky, leaving the jungle bottom covered in darkness with only a few bio-luminescent fungi to illuminate it. Along with fertile brown soil and small round hills, thick grass covers the ground and ledges like a neat blanket.
Like most other Hidden Islands, Hidden Island 7 is a short stage which can be finished in less than a minute. The stage is mainly loaded with mushrooms to bounce on and encompasses most of the stage's navigation. As hazards, Spikes and Pteras are placed around the mushrooms. Lesser gimmicks here also includes Grind Rails and Dash Rings.
The player first moves down a solid path before coming to a wide section consisting mostly of mushrooms which must be crossed. The mushrooms are laid out in two layers, so the player can take both upper and lower routes. At the end of this section, the player has to go through a lower passage and then climb a shaft with mushrooms. This leads to some more widespread mushrooms over a bottomless pit which will take the player to the Treasure Chest.