Biomes/Levels

So like Zelda, 8 levels. Different "biomes"/themes.

Forest

Capability: Fire. Like the Candle in Zelda, burn things, light torches, etc.
Cave

Capability: Ball. A protective ball: creatures won't hurt you while it's engaged, instead they push you and you roll away. No active movement. Opens the door for physics puzzles (less friction! big pushers!)
Beach

Capability: Shovel. Uncover buried things?
Underwater

Capability: Scuba. Allow you to travel underwater, open more ways to go.
Snow
Desert
Jungle

Capability: Hook Good old hook-shot. Cross large distances when there is no other way.
Tech: Spark