Rigidbody2d not falling once in the air

Hi all,

I am currently learning how to create a 2d game using the new 2d feaures that came with 4.3.
I have a script which allows the character to move left and right, and also to jump (well kind of). The problem is, is that once the character is in mid-air; it does not fall…instead just stays at whatever position it got to.

Here is the script I am using:

using UnityEngine;
using System.Collections;

public class PlayerController : MonoBehaviour
	private Transform groundCheck;			// A position marking where to check if the player is grounded.
	private Animator animator;
	private bool grounded = false;			// Whether or not the player is grounded.
	public bool jump = false;
	float vertSpeed = 0.0f;
	float gravity = 20.0f;
	private int jumpHeight = 500;
	// Use this for initialization
	void Start()
		groundCheck = transform.Find("groundCheck");
		animator = this.GetComponent<Animator>();

	// Update is called once per frame
	void Update()
		// The player is grounded if a linecast to the groundcheck position hits anything on the ground layer.
		grounded = Physics2D.Linecast(transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Ground"));
		//if (Input.GetAxis("Vertical") > 0.0f && grounded)
			//jump = true;
		if(Input.GetButtonDown("Jump") && grounded)
			jump = true;

	void FixedUpdate()
		var vertical = Input.GetAxis("Vertical");
		var horizontal = Input.GetAxis("Horizontal");
		float h = Input.GetAxis("Horizontal");
		if (Input.GetAxis("Horizontal") > 0.0f)
			animator.SetInteger("Direction", 0);
			rigidbody2D.AddForce(Vector2.right * h * 120);
			//rigidbody2D.AddForce(transform.forward * 100);
		if (Input.GetAxis("Horizontal") < 0.0f)
			animator.SetInteger("Direction", 1);
			rigidbody2D.AddForce(Vector2.right * -120);
		if (Input.GetAxis ("Vertical") > 0.0f)
			rigidbody2D.AddForce(Vector2.up * vertical * 500);




And here is a screenshot of how my character is set up:



In addition, when I set the gravity to higher than 0; my character just floats up perpetually forever?

Use the inspector to set gravity scale to a non-zero value.