Well they should, because with just 3 co-ordinates you would be able to define the point in space and that is not enough. Dimension refers to the minimum number of independent variables that must be used to define a given point.
Anyho, a little sense of humor would not have killed you you know.
The game is actually two dimensional in the sense that videos are considered three dimensional. The independent variables involved are the 1-D line and time.
(Sorry just got up from studying signal processing, couldn't help but point that out).
Anyho, a little sense of humor would not have killed you you know.