Donkey Kong 64/Gloomy Galleon

In the cannon room (the room with Lanky's blueprint), STVW can be used on one of the walls near the entrance. After entering the wall, swim to the right under the ramp leading to the level's entrance and you can get to the lighthouse area. Video (#6)
Chunky can pull himself up to the deck of the cannon room even if the water level is low. Video (#3)
You can use STVW in the lighthouse area to get to either the cannon room or the sunken ship area. Video (#5)
You can use STVW on the wall of the 5-door ship farthest from the seal to access any of the rooms. Tiny and Lanky, however, can simply use STVW to get through their respective gates. Video (#2)
You can use STVW to swim through the gate leading to the room with the mermaid's pearls. Once inside, you can use STVW on one of the back walls to get out. Video (#3)
You can use STVW on the wall opposite the entrance of Tiny's submarine to get in without using Mini Monkey.
You can enter the chest with the mermaid's pearls with STVW. Video (#4)
You can enter the 2-door ship by using STVW on the left wall (left as you approach from the main area). Video (#2)
Inside Lanky's room of the 2-door ship, you can use STVW to get behind the gate and reach the Golden Banana. You can then use STVW to get out. Video (#1)
You can get out of bounds in Cranky's area by walking into the left wall leading to the room with Chunky's Golden Banana and a fairy. The camera doesn't want you to, but it seems to calm down if you use Orangstand. Video