No, he meant a different amount of tiles so the game window is vertical, not horizontal, for example 11 x 15. In his example what really happened is that several tiles are hidden by the sidebars due to a bug and his game window is showing about 9 x 11 tiles only, missing a considerable chunk on each side. Needless to say, a 15 x 11 window forced to vertical would mean stretched and disproportional sprites that would look horrible.