My implementation of the Udemy Unity Course "Text101" game.

TextController.cs

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class TextController : MonoBehaviour {

	#region Unity editor fields
	[SerializeField]
	private State startingState;
	#endregion

	#region Components
	private Text text;
	#endregion

	#region Local variables
	private enum State {cell, sheets_0, mirror, lock_0, sheets_1, cell_mirror, lock_1,
	                    corridor_0, stairs_0, floor, closet_door, stairs_1, corridor_1,
	                    in_closet, stairs_2, corridor_2, courtyard, corridor_3};
	private State state;
	#endregion
	
	void Awake () {
		text = GetComponent<Text>();
	}

	void Start () {
		state = startingState;
	}

	void Update () {
		switch(state) {
			case State.cell:        state_cell();           break;
			case State.sheets_0:    state_sheets_0();       break;
			case State.mirror:      state_mirror();         break;
			case State.lock_0:      state_lock_0();         break;
			case State.sheets_1:    state_sheets_1();       break;
			case State.cell_mirror: state_cell_mirror();    break;
			case State.lock_1:      state_lock_1();         break;
			case State.corridor_0:  state_corridor_0();     break;
			case State.stairs_0:    state_stairs_0();       break;
			case State.floor:       state_floor();          break;
			case State.closet_door: state_closet_door();    break;
			case State.stairs_1:    state_stairs_1();       break;
			case State.corridor_1:  state_corridor_1();     break;
			case State.in_closet:   state_in_closet();      break;
			case State.stairs_2:    state_stairs_2();       break;
			case State.corridor_2:  state_corridor_2();     break;
			case State.courtyard:   state_courtyard();      break;
			case State.corridor_3:  state_corridor_3();     break;
			default: throw new MissingReferenceException("State not implemented");
		}
	}

	#region State handler methods
	void state_cell() {
		text.text = "You wake up in a cell, with no idea how you got there. " +
			"The only interesting things in the room are the bed's dirty " + 
			"sheets, a mirror on the wall, and the door, which will " + 
			"definately be locked." +
			"\n\n" +
			"Press 'S' to examine the Sheets, 'M' to examine the Mirror, " + 
			"or 'L' to try the Locked door.";
		if      (Input.GetKeyDown(KeyCode.S))   {state = State.sheets_0;}
		else if (Input.GetKeyDown(KeyCode.M))   {state = State.mirror;}
		else if (Input.GetKeyDown(KeyCode.L))   {state = State.lock_0;}
	}
	void state_sheets_0() {
		text.text = "There isn't anything special about these sheets. They're " + 
			"standard issue, after all." +
			"\n\n" +
			"Press 'R' to Return.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.cell;}
	}
	void state_mirror() {
		text.text = "There isn't anything special about the mirror -- wait! " +
			"Pulling on the side of the mirror, it swings into the room, " +
			"revealing a small hole in the wall with a key in it. " +
			"This may come in handy." +
			"\n\n" +
			"Press 'R' to Return or 'T' to Take the key.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.cell;}
		else if (Input.GetKeyDown(KeyCode.T))   {state = State.cell_mirror;}
	}
	void state_lock_0() {
		text.text = "There is no handle on the door. However, the keyhole is " +
			"visible from inside. If only you had some way to " +
			"find a key..." +
			"\n\n" +
			"Press 'R' to Return.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.cell;}
	}
	void state_sheets_1() {
		text.text = "How do you expect to use a key on bedclothes? A key is for " +
			"doors, not linens." +
			"\n\n" +
			"Press 'R' to Return.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.cell_mirror;}
	}
	void state_cell_mirror() {
		text.text = "You are in your cell, the mirror has fallen off its hinges, " +
			"and you have a small key." +
			"\n\n" +
			"Press 'S' to examine your Sheets or 'L' to try the Locked door.";
		if      (Input.GetKeyDown(KeyCode.S))   {state = State.sheets_1;}
		else if (Input.GetKeyDown(KeyCode.L))   {state = State.lock_1;}
	}
	void state_lock_1() {
		text.text = "You stick your key in the keyhole and -- this just might work! " +
			"However, you suddenly feel like this might be a bad idea." +
			"\n\n" +
			"Press 'R' to Return to your room or 'O' to Open the door.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.cell_mirror;}
		else if (Input.GetKeyDown(KeyCode.O))   {state = State.corridor_0;}
	}
	void state_corridor_0() {
		text.text = "You've escaped from your room, but you're not out of the fire " +
			"yet. You see a glint of light bounce off the floor, a stairwell on your " +
			"left, and a closet door." +
			"\n\n" +
			"Press 'S' to go to the Stairs, 'F' to inspect the Floor, or 'C' to " +
			"check out the Closet.";
		if      (Input.GetKeyDown(KeyCode.S))   {state = State.stairs_0;}
		else if (Input.GetKeyDown(KeyCode.F))   {state = State.floor;}
		else if (Input.GetKeyDown(KeyCode.C))   {state = State.closet_door;}
	}
	void state_stairs_0() {
		text.text = "These stairs go up, but if you go up you are going away from " +
			"your intended target -- freedom. You don't really want to go up the " +
			"stairs." +
			"\n\n" +
			"Press 'R' to Return to the hallway.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.corridor_0;}
	}
	void state_floor() {
		text.text = "That glint of light was a hairclip on the ground. Might as well " +
			"take it, it's not like someone needs it." +
			"\n\n" +
			"Press 'R' to Return or 'H' to take the Hairclip.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.corridor_0;}
		else if (Input.GetKeyDown(KeyCode.H))   {state = State.corridor_1;}
	}
	void state_closet_door() {
		text.text = "There's a closet door, probably a janitor closet, but it's " +
			"locked. You seem to have a problem with locked doors. Possibly you " +
			"could open the door if you had something to pick the lock with." +
			"\n\n" +
			"Press 'R' to Return to the hallway.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.corridor_0;}
	}
	void state_stairs_1() {
		text.text = "You see the stairs go up. However, the voice of your " +
			"subconsious tells you \"This isn't a good idea, You still have work " +
			"to do here.\"" +
			"\n\n" +
			"Press 'R' to Return to the hallway.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.corridor_1;}
	}
	void state_corridor_1() {
		text.text = "You're still stranded, but now you have a women's fashion " +
			"accessory. Whoop-de-do." +
			"\n\n" +
			"Press 'S' to check the Stairwell or 'C' to try the Closet.";
		if      (Input.GetKeyDown(KeyCode.S))   {state = State.stairs_1;}
		else if (Input.GetKeyDown(KeyCode.C))   {state = State.in_closet;}
	}
	void state_in_closet() {
		text.text = "You managed to pick the lock and now can enter the closet. " +
			"There's not much in there but a janitor uniform. It looks to be " +
			"about your size." +
			"\n\n" +
			"Press 'R' to Return to the hallway, or 'D' to Dress in the uniform.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.corridor_2;}
		else if (Input.GetKeyDown(KeyCode.D))   {state = State.corridor_3;}
	}
	void state_stairs_2() {
		text.text = "You are in the stairwell. You could go down, but you might " +
			"fare better if you looked like you belong here rather than still " +
			"dressed as a prisoner." +
			"\n\n" +
			"Press 'R' to Return to the hallway.";
		if      (Input.GetKeyDown(KeyCode.R))   {state = State.corridor_2;}
	}
	void state_corridor_2() {
		text.text = "You stand in a mostly featureless hallway, except for a " +
			"mostly featureless stairwell, the door to your old cell, and the " +
			"mostly featureless janitor's closet. You wonder how many different " +
			"flavor texts there are for this hallway." +
			"\n\n" +
			"Press 'S' to check out the Stairs, or 'R' to Return to the closet.";
		if      (Input.GetKeyDown(KeyCode.S))   {state = State.stairs_2;}
		else if (Input.GetKeyDown(KeyCode.R))   {state = State.in_closet;}
	}
	void state_courtyard() {
		text.text = "You safely exit the building undetected. Now you are free! " +
			"You think." +
			"\n\n" +
			"Thank you for playing this game. Built as part of the Udemy Unity " +
			"Course." +
			"\n\n" +
			"Press 'P' to Play again.";
		if      (Input.GetKeyDown(KeyCode.P))   {state = startingState;}
	}
	void state_corridor_3() {
		text.text = "You enter the corridor and notice the stairwell once more. " +
			"You should be able to exit now that you look like an everyday worker." +
			"\n\n" +
			"Press 'S' to take the Stairs or 'U' to Undress from the uniform.";
		if      (Input.GetKeyDown(KeyCode.S))   {state = State.courtyard;}
		else if (Input.GetKeyDown(KeyCode.U))   {state = State.in_closet;}
	}
	#endregion
}