No, you don't need a trailer to know how Tetris works, but you do need one to see the surprisingly numerous array of extra modes in the 3DS game, Tetris Axis. The bonus games range far beyond the normal "Tetris with some blocks already laid out," including weirdo modes like one in which you guide a single game piece through a racetrack, a game about building up a cylindrical tower, and even AR modes that put the Tetris playing field on your desk.
We're sure a lot of people will balk at the idea of another retail Tetris, but this is a good effort toward filling that cartridge. Also, there's a dancing monkey.