The majority of the level takes place underwater, which makes it a considerably difficult level. Jumps are higher, and it takes much longer to descend, giving fast enemies a noticeable advantage. Water currents are also present in parts, and can slow Mickey even more.
- This level is regarded as one of the most, if not THE most difficult level in the game due to slower movement, a significantly large number of enemies, the fast movement of most enemies, spikes covering many areas, the fact that the player takes more damage than normal when hit, and the fact that there are not as many health pick ups in the level as there are in other levels.
- Reaching Ursula is also one of the most difficult sections of the level due to the fact that the platforms the player must fall through are rather small. As such, the player must pass through them with the right timing, or the water current may push the player into the spikes.