WATCH THE VIDEO!
Info prior to watching: Start the map "Over the Rainbow" in the Jibberish Jungle (the map is fairly flat with no enemies to worry about). Hold the -RT button from the start and keep it held down until the end of the level (watch my video for exact details and jumps). Be extremely cautious not to suddenly change directions otherwise this achievement might not count. The achievement may not pop until after your score has been calculated at the end so do not worry if it does not pop as soon as you finish the level (again you can reference the video to see this).