Doorstop Dash is the second level of Donkey Kong Country 3: Dixie Kong's Double Trouble, and is located in Lake Orangatanga.
In order for the Kongs to progress through this mill, they must pull levers to open doors. But the doors only stay open for a short time, so they have to get through them before they close. All in all, it shouldn't be much trouble, as it's only the second level. Buzzes make their debut here, but they're only a minor annoyance. Many Sneeks also make their home here.