FinalBattle/GameState.cs

public sealed class GameState
{
    public static readonly Lazy<GameState> _instance = new Lazy<GameState>(() => new GameState());
    private GameState() {}
    public static GameState Instance
    {
        get {return _instance.Value;}
    }

    public List<Character> heros = new List<Character>();
    public List<Character> monsters = new List<Character>();
    public List<Character> heroRemove = new List<Character>();
    public List<Character> monsterRemove = new List<Character>();
    public int currentRound = 1;
    public bool gameOver = false;
    public bool herosAIControl = false;
    public bool monstersAIControl = true;
    public bool lastRound = false;

    public void Run()
    {
        Rounds(currentRound);
        while (gameOver == false)
        {
            GameOver();
            if (gameOver == true)
            {
                return;
            }
            if (heros.Any())
            {
                foreach (Character hero in heros)
                {
                    hero.isTurn = true;
                    Actions.Instance.GetAction(hero);
                    CheckDead();
                    hero.isTurn = false;
                }
            }
            foreach (Character monster in monsterRemove)
            {
                monsters.Remove(monster);
            }
            if (monsters.Any() && heros.Any())
            {
                foreach (Character monster in monsters)
                {
                    monster.isTurn = true;
                    Actions.Instance.GetAction(monster);
                    CheckDead();
                    foreach (Character hero in heroRemove)
                    {
                        heros.Remove(hero);
                    }
                    if (!heros.Any())
                    {
                        break;
                    }
                    monster.isTurn = false;
                }
            }
        }
    }

    public void DisplayStatus()
    {
        Console.WriteLine("================================= BATTLE =================================");
        foreach (Character hero in GameState.Instance.heros)
        {
            if (hero.isTurn == true)
            {
                Console.ForegroundColor = ConsoleColor.Cyan;
            }
            Console.WriteLine($"{hero.name, -20}    HP: {hero.currentHP}/{hero.maxHP}");
            Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("----------------------------------- VS -----------------------------------");
        }
        foreach (Character monster in GameState.Instance.monsters)
        {
            if (monster.isTurn == true)
            {
                Console.ForegroundColor = ConsoleColor.Red;
            }
            if (monster.name == "The Uncoded One")
            {
                Console.WriteLine($"{monster.name, 59}      HP: {monster.currentHP, 2}/{monster.maxHP, -2}");
                Console.ForegroundColor = ConsoleColor.White;
            }
            else
            {
                Console.WriteLine($"{monster.name, 59}        HP: {monster.currentHP}/{monster.maxHP, -2}");
                Console.ForegroundColor = ConsoleColor.White;
            }
        }
    }

    public void CheckDead()
    {
        foreach (Character hero in heros)
        {
            if (hero.currentHP <= 0)
            {
                hero.dead = true;
                heroRemove.Add(hero);
            }
        }

        foreach (Character monster in monsters)
        {
            if (monster.currentHP <= 0)
            {
                monster.dead = true;
                monsterRemove.Add(monster);
            }
        }
    }

    public void GameOver()
    {
        if (currentRound == 3)
        {
            lastRound = true;
        }
        if (!heros.Any())
        {
            gameOver = true;
            MonstersWin();
            return;
        }
        if (!monsters.Any() && lastRound == false)
        {
            currentRound++;
            Console.WriteLine($"Round {currentRound}");
            Rounds(currentRound);
            return;
        }
        if (!monsters.Any() && lastRound == true)
        {
            gameOver = true;
            HerosWin();
            return;
        }
    }

    public void Rounds(int currentRound)
    {
        if (currentRound == 1)
        {
            Skeleton skeleton1 = new Skeleton();
            monsters.Add(skeleton1);
        }
        if (currentRound == 2)
        {
            Console.Clear();
            Console.WriteLine("You are victorious in your first battle!");
            Thread.Sleep(2000);
            Console.WriteLine("\nAs you make your way deeper into the Uncoded One's fortress" 
                    + "\nmore enemies appear, blocking your way forward to defeat their master...");
            Console.WriteLine("\n\nPress Enter to continue...");
            Console.ReadLine();
            Skeleton skeleton1 = new Skeleton();
            Skeleton skeleton2 = new Skeleton();
            monsters.AddRange(skeleton1, skeleton2);
        }
        if (currentRound == 3)
        {
            Console.Clear();
            Console.WriteLine("You have completed the second battle in your assualt on the"
                    + " Uncoded One's fortress!");
            Thread.Sleep(2000);
            Console.WriteLine("\nAs you move deeper into the fortress, you come upon two great"
                    + "\nsteel doors set into a wall of stone. You push open the doors, and" 
                    + "\nfind yourself in the Uncoded One's throne room. The Uncoded One stands"
                    + "\nfrom his throne of blackened steel and hisses, \"You have finally"
                    + "\nappeared before me True Programmer. Now you will die, and the world"
                    + "\nwill be mine!\"");
            Console.WriteLine("\n\nPress Enter to continue...");
            Console.ReadLine();
            Skeleton skeleton1 = new Skeleton();
            Skeleton skeleton2 = new Skeleton();
            Skeleton skeleton3 = new Skeleton();
            UncodedOne uncodedOne = new UncodedOne();
            monsters.AddRange(skeleton1, skeleton2, skeleton3, uncodedOne);
        }
    }

    public void HerosWin()
    {
        Console.Clear();
        Thread.Sleep(2000);
        Console.WriteLine("As you strike the Uncoded One down, the sky brightens and the"
                + " miasma\nsurrounding his dark fortress begins to lift...\n\n"
                + "You are victorious!\n\nTrue Programming has been restored to the lands, and"
                + " the people\ncan now improve their lives through the various arts of code you\n"
                + "have helped restore...");
        Console.WriteLine("\nPress Enter to exit your final challenge, True Programmer!");
        Console.ReadLine();
    }

    public void MonstersWin()
    {
        Console.Clear();
        Thread.Sleep(2000);
        Console.WriteLine("You have been brutally struck down by the Uncoded One and his evil\n"
                + "minions. This is a devastating loss for the all the people whom you have helped...\n"
                + "The Uncoded One will now reign supreme in unchecked war against the entire land, and\n"
                + "\nTrue Programming may forever be lost...");
        Console.ReadLine();
    }
}