If you are use font objects in the bge, the material color did not work (You can delete the material).
You must change the object color in the “Object” tab (cube symbol) --> “Display” --> “Object Color”.
If you use a bitmap font, then enable “Shadeless” in the material.
If you use font objects and want text vertical text with vertical letters rotate the text 90 degrees.
If you use font objects and want text vertical text with horizontal letters. Then you need a script that splits the text in separate letters and add the single letters among each other.