Choose your own adventure

Been continuing from the choose your own adventure from C# lesson, and I am getting these continuous error that I cannot seem to solve. Could anyone help me? Thanks in advance! My code is right below the error picture.

using System;

namespace ChooseYourOwnAdventure
{
  class Program
  {
      static void Main(string[] args)
    {
      /* THE MYSTERIOUS NOISE */

      // Start by asking for the user's name:
      Console.Write("What is your name?: ");
      string name = Console.ReadLine();
      Console.WriteLine($"Hello, {name}! Welcome to our story.");
      Console.WriteLine("It begins on a cold rainy night. You're sitting in your room and hear a noise coming from down the hall. Do you go investigate?");
      Console.WriteLine("Type YES or NO:");
      string noisechoice = Console.ReadLine();
      string noiseChoice = noisechoice.ToUpper();
      if(noiseChoice == "NO")
      {
        Console.WriteLine("Not much of an adventure if we don't leave our room!");
        Console.Write("THE END.");
      }
      else if(noiseChoice == "YES")
      {
        Console.WriteLine("You walk into the hallway and see a light coming from under a door down the hall. You walk towards it. Do you open it or knock?");
      }
        Console.WriteLine("Type OPEN or KNOCK");
        string doorchoice = Console.ReadLine();
        string doorChoice = doorchoice.ToUpper();
      if(doorChoice == "KNOCK")
      {
        Console.WriteLine("A voice behind the door speaks. It says, Answer this riddle: Poor people have it. Rich people need it. If you eat it you die. What is it?");
      Console.Write("Type your answer:");
      string riddleanswer = Console.ReadLine();
      string riddleAnswer = riddleanswer.ToUpper();
      if(riddleAnswer == "NOTHING")
      {
      Console.WriteLine("The door opens and NOTHING is there. You turn off the light and run back to your room. Suddenly, a case of stairs appear behind you. Climb it or go back to your room?");
      Console.WriteLine("Type CLIMB or ROOM.");
      string answer2 = Console.ReadLine();
      string Answer2 = answer2.ToUpper();
      if(Answer2 == "CLIMB")
      {
        Console.WriteLine("With deep breathes and after 2 hours of heavy steps, you make it to the top. You are blocked by a voice that asks you another question. ");
        Console.WriteLine("Re-arrange the letters, O O U S W T D N E J R, to spell just one word. What is it?");
        string riddleAnswer2 = Console.ReadLine();
        if(riddleAnswer2 == "just one word")
        {
          Console.WriteLine("You walk forward to a blinding light. You see an incredibly delicious looking food on the ground, but it looks too perfect. Do you eat it or keep walking.");
          Console.WriteLine("TYPE EAT or WALK.");
          string lightchoice = Console.ReadLine();
          string lightChoice = lightchoice.ToUpper();
          if(lightChoice == "EAT")
          {
          Console.WriteLine("YOU'VE BEEN POISONED!");
          Console.WriteLine("TYPE THE ANSWER TO FIND THE ANTIDOTE");
          string poisonedAnswer = Console.ReadLine();
          if(poisonedAnswer == "THE ANSWER TO FIND THE ANTIDOTE")
          {
            Console.WriteLine("Your life has been restored. You decide to walk more afterwards.");
            
          }
            else
            {
              Console.WriteLine("You burn into a billion ashes.");
              Console.WriteLine("Try Again.");
            }
          }
          else if(lightChoice == "WALK")
          {
            Console.WriteLine("You decide to walk further and ignore the food left on the ground. This seems like a supernatural world. The world around you forms as you continue walking down the pathway. You are unable to talk, as it seems like no words come to your memory. You come across a hall and at the end appears a door with a light under it. Do you knock or open?");
            Console.WriteLine("Type KNOCK or OPEN");
            string Answer3 = Console.ReadLine();
          }
          
        }
        else
        {
          Console.WriteLine("Before you know it, you begin to evaporate into dust. Seconds later your existence is gone.");
          Console.WriteLine("THE END.");
        }
      }
      }
      else
     {
      Console.WriteLine("You answered incorrectly. The door doesn't open and the floor opens and you fall. Try again.");     
      Console.Write("THE END.");
     }
                          

      }
      else if(doorChoice == "OPEN");
      {
        Console.WriteLine("The door is locked! See if one of your three keys will open it.");
        Console.Write("Enter a number (1-3):");
        string keychoice = Console.ReadLine();
        string keyChoice = keychoice.ToUpper();
        switch(keyChoice)
        {
        case "1":
        Console.WriteLine("You choose the first key. Lucky choice! The door opens and NOTHING is there. Strange... THE END.");
        break;
        
        case "2":
            {
        Console.WriteLine("You choose the second key. You hear a click behind you. You turn around and see a hooded figure. Flight or fight.");
        Console.WriteLine("Enter FLIGHT or FIGHT:");
        string hoodedoption = Console.ReadLine();
        string hoodedOption = hoodedoption.ToUpper();
        if(hoodedOption == "FIGHT")
        {
          Console.WriteLine("Letters will appear! Enter them as fast as you can to throw combat. Failure to do so will result in a loss. All is capital.");
          Console.WriteLine("P");
         string combat1 = Console.ReadLine();
          if(combat == "P")
          {
          Console.WriteLine("Your enemy blocks the attack!");
          }
          else
          {
          Console.WriteLine("Your enemy whacks a superior punch. You are too hurt to get up. THE END.");
          }
          System.Threading.Thread.Sleep(3000);
          Console.WriteLine("K");
          string combat2 = Console.ReadLine();
          if(combat2 == "K")
          {
          Console.WriteLine("Good hit, your opponent nearly fainted!");
          }
          else
          {
            Console.WriteLine("Time is up for you. THE END.");
          }
          System.Threading.Thread.Sleep(3000);
          Console.WriteLine("O");
          string combat3 = Console.ReadLine();
          if(combat3 == "O")
          {
            Console.WriteLine("HES WEAK! QUICK! TYPE PKOPKO AND DEFEAT HIM!");
            string combatFinish = Console.ReadLine();
            if(combatFinish == "PKOPKO")
            {
              Console.WriteLine("∀ʞWԀOQ ˙ɹǝʇɐl ʇᴉ pǝǝu llᴉʍ no⅄ ˙ǝpoɔ sᴉɥʇ ǝʞɐ┴ ˙ʎɥʇɹoʍ ǝɹɐ no⅄ ˙ǝlqᴉssodɯI ˙ǝɯ pǝʇɐǝɟǝp ǝʌɐɥ no⅄");
            Thread.Sleep(2000); 
              Console.WriteLine("You instantly decide to go back to your room, petrified. You close your eyes and the next day, it all seems normal. THE END.");
            }
          }
          }
             else
            {
             ("You are in need of rest. Eventually you faint. THE END.");
            }
          
            break; 
            }
        
            
              
              case "3":
              Console.WriteLine("It doesn't seem to work. Jam it in?");
              Console.WriteLine("Type YES OR NO.");
              string jam = Console.ReadLine();
              string Jam = jam.ToUpper();
              if(Jam == "YES")
              {
                Console.WriteLine("You broke the handle.");
              }
              else if(Jam == "NO")
              {
                Console.WriteLine("You try putting it more carefully. It results in absolutely nothing. Congratulations.");
              }
            break;
            
            default:
          {
            Console.WriteLine("You serious?");
          }
            break;
            }
            else
          {
          Console.WriteLine("Weak, but still able to fight. You get thrown a massive punch. THE END.");
          }
        
        
        }
      }
    
     
    }
  }

}