Help Understand Space Invaders Command Propmt Game

#include <iostream>
#include "windows.h"
#include <time.h>

using namespace std;

char Map[20][20] =
{

	"###################",
	"#                 #",
	"#   @ @ @ @ @ @   #",
	"#    @ @ @ @ @    #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#        W        #",
	"###################"

};

bool endGame = false;
int gameSpeed = 100;
int randomNum;
int maxHealth = 200;
int yourHealth = maxHealth;

int main()
{
	system("color 0a");

	while(!endGame)
	{

		srand(time(0));
		system("cls");
		for(int y = 0; y < 20; y++)
		{

			cout << Map[y] << endl;

		}

		cout << "Health " << yourHealth << "/" << maxHealth;

	for(int y = 0; y < 20; y++)
	{

		for(int x = 0; x < 20; x++)
		{

			switch(Map[y][x])
			{
			case 'W':

				if(GetAsyncKeyState(VK_LEFT) != 0)
				{
					int newX = x - 1;

					switch(Map[y][newX])
					{
					case ' ':
						Map[y][x] = ' ';
						x--;
						Map[y][newX] = 'W';

					break;
					}
				}

				if(GetAsyncKeyState(VK_RIGHT) != 0)
				{
					int newX = x + 1;

					switch(Map[y][newX])
					{
					case ' ':
						Map[y][x] = ' ';
						x++;
						Map[y][newX] = 'W';
						break;
					}
				}

				if(GetAsyncKeyState(VK_SPACE) != 0)
				{
					y--;
					Map[y][x] = '^';
				}

			break;

			case '^':

				Map[y][x] = ' ';
				y--;

				if(Map[y-1][x] != '#' && Map[y][x] != '@')
				{
					Map[y][x] = '^';
				}else if(Map[y][x] == '@')
				{
					Map[y][x] = ' ';
				}

			break;

			case '@':
				randomNum = rand() % 50 + 1;
				
				if(randomNum == 1)
				{
					y++;
					Map[y][x] = '*';
				}
			break;

			case '*':
				Map[y][x] = ' ';
				y++;

				if(Map[y][x] != '#' && Map[y][x] != 'W')
				{
					Map[y][x] = '*';
				}else if(Map[y][x] == 'W')
				{
					yourHealth -= 20;
				}

			break;
			}
		}
	}

	if(yourHealth <= 0)
	{
		endGame = true;
	}
	Sleep(gameSpeed);
	}

	system("cls");
	cout << "You lost!" << endl;

	cin.get();

	return 0;
}

#include <iostream>
#include "stdlib.h"
#include <time.h>

using namespace std;
/*Declare array established starting position of game objects
 Play with this to add more bad guys or change where they start!*/
char Map[20][20] =
{

	"###################",
	"#                 #",
	"#   @ @ @ @ @ @   #",
	"#    @ @ @ @ @    #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#                 #",
	"#        W        #",
	"###################"

};
/*Declare some variables
*is game over
 *how fast game plays
 * and your health
 */

bool endGame = false;
int gameSpeed = 100;
int randomNum;
int maxHealth = 200;
int yourHealth = maxHealth;

int main()
{
	system("color 0a");
/*Loop through game until game ends*/
	while(!endGame)
	{

		srand(time(0));
		/*Pass Clear Screen to OS*/
		system("cls");
		/*Loop through map and print to screen*/
		for(int y = 0; y < 20; y++)
		{

			cout << Map[y] << endl;

		}
/*Print health to screen*/
		cout << "Health " << yourHealth << "/" << maxHealth;
/*Loop through Y-Coords of map*/
	for(int y = 0; y < 20; y++)
	{
/*Loop through X-Coords for each Y-coord of map*/
		for(int x = 0; x < 20; x++)
		{
/*Switch checks which character is found
			 in current coordinate*/
			switch(Map[y][x])
			{
				/*If it is W then it is player*/
			case 'W':
/*Did you press left*/
				if(GetAsyncKeyState(VK_LEFT) != 0)
				{
					int newX = x - 1;
/*Move player one space left if new coord
					 is white space and not a wall*/
					switch(Map[y][newX])
					{
					case ' ':
						Map[y][x] = ' ';
						x--;
						Map[y][newX] = 'W';

					break;
					}
				}
/*did you press right*/
				if(GetAsyncKeyState(VK_RIGHT) != 0)
				{
					int newX = x + 1;
/*Move player one space right if new coord
					 is white space and not a wall*/
					switch(Map[y][newX])
					{
					case ' ':
						Map[y][x] = ' ';
						x++;
						Map[y][newX] = 'W';
						break;
					}
				}
/*Did you press space*/
				if(GetAsyncKeyState(VK_SPACE) != 0)
				{
					/*Create bullet above player*/
					y--;
					Map[y][x] = '^';
				}

			break;

					/*If it is ^ then it is a bullet*/
			case '^':
/*Return old coord to white space*/
				Map[y][x] = ' ';
				y--;
					
/*Check for colission with wall and bad guys*/
				if(Map[y-1][x] != '#' && Map[y][x] != '@')
				{
					/*Write bullet ti bew ciird*/
					Map[y][x] = '^';
				}else if(Map[y][x] == '@')
						/*Check if collission was a badguy*/
				{
					/*Destroy bullet and badguy*/
					/*Want your bullet to keep going? set to '^'*/
					Map[y][x] = ' ';
				}

			break;

					/*@ is bad guy*/
			case '@':
					/*Generate random number between 1 and 50*/
				randomNum = rand() % 50 + 1;
				/*if random number is 1*/
				if(randomNum == 1)
				{
					/*create bomb bellow the bad guy*/
					y++;
					Map[y][x] = '*';
				}
			break;
/** is a bomb*/
			case '*':
					/*remove bomb from old position*/
				Map[y][x] = ' ';
				y++;
/*Check for collision*/
				if(Map[y][x] != '#' && Map[y][x] != 'W')
				{
					/*if no collision set bomb one space down*/
					Map[y][x] = '*';
				}else if(Map[y][x] == 'W')
				{
					/*if collision with player reduce health by 20*/
					yourHealth -= 20;
				}

			break;
			}
		}
	}
/*If health is equal to or less than 0*/
	if(yourHealth <= 0)
	{
		/*set endgame variable*/
		endGame = true;
	}
		/*Pause for duration set as game speed*/
	Sleep(gameSpeed);
		
	/*repeat loop*/}
/*Clear the screen*/
	system("cls");
	/*GAME OVER*/
	cout << "You lost!" << endl;
/*Wait for key press to end*/
	cin.get();

	return 0;
}