onCollsionEnter specifying objects? - unity3d

Question

I'm currently making a infinite runner type game for a class project and I need some help with collisions.
The game is set up as a 2d platform where a character is running (or made to look like they're running with a scrolling texture) through an infinite tunnel. The player has to avoid obstacles similar to Flappy Bird using jumps. The script I'm using at the moment is setup so that when the player collides with obstacles the game will reload.
The issue:
The issue is that the code I've used applies to all collisions so when the player hits the ground platform the game reloads.
What I want to happen:
I want the character to be able to run on a platform and die when he hits the a specific obstacle.
So I'm think I need to specify a GameObject to collide with?
This is my current code:
// Update is called once per frame
void Update ()
{
// Jump
if (Input.GetKeyUp("space"))
{
rigidbody2D.velocity = Vector2.zero;
rigidbody2D.AddForce(jumpForce);
}
// Die by being off screen
Vector2 screenPosition = Camera.main.WorldToScreenPoint(transform.position);
if (screenPosition.y > Screen.height || screenPosition.y < 0)
{
Die();
}
}
// Die by collision
void OnCollisionEnter2D(Collision2D other)
{
Die();
}
void Die()
{
Application.LoadLevel(Application.loadedLevel);
}
}

Answer 1

Use tags. For example, use a terrain tag for the ground. If the object tag is terrain, then don't die.
Here is a simple example:
void OnCollisionEnter2D(Collision2D other)
{
if (other.collider.tag == "Terrain")
{
Debug.Log("Don't die!");
}
else
{
Debug.Log("Die!");
}
}