That is one way of numbering dimensions, in a certain model of the universe. However, in a 2d game, time might be a "third dimension". Or time might be sufficie

That is one way of numbering dimensions, in a certain model of the universe. However, in a 2d game, time might be a "third dimension". Or time might be sufficiently distinct in some model that it does not behave like a dimension at all. If I write an equation, and graph it, it has as many dimensions as variables. Those variables might have nothing to do with time OR space.