Player Movement
Here is an article on player movement. How to create movement for a 2D player; be it diagonal, non diagonal or platformer.
Top Down 8 Directional
The best way to deal with player input in Unity is using the [Input.GetAxis](https://docs.unity3d.com/ScriptReference/Input.GetAxis.html) method. You pass it a string value, "Vertical" or "Horizontal" and it returns a positive or negative float value. It’s great because it works with whatever inputs are configured via the Input Manager. This means it works for WASD, arrows, joystick or mouse!
Leaving the desired inputs to the Input Manager saves a lot of refactor headaches. If I change mind later on I can do it as a configuration rather than alter the source code.
void Update(){
rb.velocity = new Vector2(Input.GetAxis("Vertical") * moveSpeed, Input.GetAxis("Horizontal") * moveSpeed);
}