How can I have the player be able to kill an enemy by jumping on top of it?

Questions & Answers
1

I am making a 2d style platformer but in 3d and I want the player to kill an enemy by jumping on top of it. Right now the enemy is just simple box. I figured out 3 solutions that kind of work.

The first one was creating an empty object, giving it a box collider, checking the is trigger box put it on top of the enemy, and made it a child of the enemy. Then I wrote some code that when the player hit the empty object the parent will be destroyed by checking if the player collided with an object at layer x. That worked but if the player ran into the enemy a few times the enemy would just die so I scrapped this.

The second solution was checking if the player is traveling down and hit the enemy the enemy will be destroyed. The problem with this is that if the player hits the enemy on the side while falling the enemy dies.

private void OnCollisionEnter(Collision collision)
    {
        Enemy hitEnemy = collision.gameObject.GetComponent<Enemy>();
        
        if (hitEnemy && rigidbodyComponent.velocity.y < 0)
        {
            Destroy(hitEnemy.gameObject);
        }
    }

Third solution was a mix of the the first 2 but the enemy still dies when hitting the side but a little higher up:

private void OnTriggerEnter(Collider other)
    {
        if (other.gameObject.tag == "Enemy" && rigidbodyComponent.velocity.y < 0)
        {
            Destroy(other.transform.parent.gameObject);
        }
    }
2

Have you considered using a smaller collider and putting it in the middle of the enemy’s top so that the player has to land squarely on top of the enemy to contact it?

Edit: an alternative solution may be to have another collider for the sides of the enemy. If a collision happens on the sides collider and the damaging collider simultaneously, then ignore it. But if a collision only happens to the damaging collider then register the damage.