Unity 2D Top down Movement in 30 seconds

Create a 2D object and add a Rigidbody2D to it (change the gravity scale to 0), and then attach the following script:

using UnityEngine;

public class TopDownMovement : MonoBehaviour
{
    public float moveSpeed = 5f;

    private Rigidbody2D rb;
    private Vector2 movement;

    void Start()
    {
        rb = GetComponent<Rigidbody2D>();
    }

    // Update is called once per frame
    void Update()
    {
        // Get input from player
        movement.x = Input.GetAxis("Horizontal");
        movement.y = Input.GetAxis("Vertical");

        // Move the character
        rb.MovePosition(rb.position + movement * moveSpeed * Time.fixedDeltaTime);
    }
}

Save it and press Play. Use the Arrow keys or AWSD to move.