How would I make my GameObject move diagonally

Questions & Answers
1

Please , watch this video to have idea of what am trying to achieve. Here is a link to the video, Avoid the Black - New Addictive Android Game - YouTube.

2

You can use:

transform.Translate(Vector3.forward * Time.deltaTime * yourSpeed * 1)

transform.Translate(Vector3.left * Time.deltaTime * yourSpeed * 1)

This would make the Gameobject move forwards and to the left.

Note: you have to use both.