Hopefully there's okay comments on things now

Assets/Ratbot.cs

@@ -9,20 +9,20 @@ public class Ratbot : MonoBehaviour
 	float lastDamageTime;
 	GameState gameState;
 	GameObject player;
-    // Start is called once before the first execution of Update after the MonoBehaviour is created
-    void Start()
-    {
+
+    void Start() {
+		// Set gameState and player objects
 		player = GameObject.FindGameObjectWithTag("Player");
 		gameState = GameObject.FindGameObjectWithTag("GameController").GetComponent<GameState>();
     }
 
-    // Update is called once per frame
-    void Update()
-    {
+    void Update() {
+		// Constantly move towards player
 		Rigidbody2D controller = GetComponent<Rigidbody2D>();
 		Vector2 direction = (player.transform.position - transform.position).normalized;
 		controller.linearVelocity = direction*moveSpeed;
     }
+
 	void OnCollisionStay2D(Collision2D collision) {
 		// Deal damage when colliding with the player on a 0.5 second cooldown
 		if (collision.gameObject.tag != "Player") return;
@@ -30,6 +30,8 @@ public class Ratbot : MonoBehaviour
 		lastDamageTime = Time.fixedTime;
 		collision.gameObject.GetComponent<Teo>().health -= damageStrength;
 	}
+
+	// Die if health below zero
 	public void Damage(float hurtyAmount) {
 		health -= hurtyAmount;
 		if (health <= 0) {