This is a tool-assisted speedrun. For more information, see http://tasvideos.org/1326M.html
Contra 4 (2007) is largely a combined remake of the early NES and SNES Contra (http://tasvideos.org/Search.html?key=Contra) titles, featuring remixed music and vastly improved visuals utilizing both screens of the DS as if they were one contiguous screen.
Watch Bill Rizer embark on a new colorful adventure in the shirtless land, this time making even less sense than ever before. To quote the game