private void OnCollisionEnter2D(Collision2D collision)
    {
        if (collision.gameObject.tag == "Enemy")
        {
            if (invincible == true)  // if player is experiencing invincible power up game loss is skipped
            {
            }
            else
            {
                levelData.gameLost();
                GameObject particles = Instantiate(deathParticles, transform.position, Quaternion.identity);

                particles.GetComponent <Renderer>().material = GameObject.FindWithTag("Player").GetComponent <SpriteRenderer>().material;                   // sets the colour of death particles to match player material
                particles.GetComponent <ParticleSystemRenderer>().material = GameObject.FindWithTag("Player").GetComponent <SpriteRenderer>().material;     // sets the colour of death particles to match player material

                Instantiate(deathAudio, transform.position, Quaternion.identity);
                Destroy(gameObject);
            }
        }
    }