Full Script

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;

import java.awt.Color;
import java.util.ArrayList;
import java.util.Random;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;

public class Falling_Game implements KeyListener{
	
	float gameSpeed = 750f;
	boolean gameOver = false;
	
	JFrame gameWindow = new JFrame();
	int[][] matrix = new int[12][5];
	JPanel[][] jPanelmatrix = new JPanel[12][5];
	
	JLabel gameOverLabel = new JLabel("Game Over");
	
	JPanel gameBoard = new JPanel();
	
	JPanel gameOverPanel = new JPanel();
    
	JButton button = new JButton("Exit");
	
	int playerLocation = 2;
	
	boolean firstOpen = true;
	
	private long startTime = System.currentTimeMillis();
	
	ArrayList<Coord> coords = new ArrayList<Coord>();//This one holds the coords of the falling blocks
	
	public void CreateGameBoard() {

		// initializing the 2D array
		for(int i = 0; i < matrix.length; i++) {
		    for(int j = 0; j < matrix[i].length; j++) {
		        matrix[i][j] = 0;
		    }
		}
		
		for(int i = 0; i < matrix.length; i++) {
		    for(int j = 0; j < matrix[i].length; j++) {
		    	//System.out.print(matrix[i][j]);
			}
			//System.out.println();
		}
		
		for (int i = 0; i < jPanelmatrix.length; i++) {
		    for (int j = 0; j < jPanelmatrix[i].length; j++) {
		        jPanelmatrix[i][j] = new JPanel();
		    }
		}
	}
	
	public void JFrameBuilder() {
		gameWindow.setVisible(true);
		gameWindow.setSize(new Dimension(300, 600));
		gameWindow.setLocationRelativeTo(null);
		gameWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		firstOpen = false;
		
		gameWindow.addKeyListener(this);
		
		gameBoard.setLayout(new GridLayout(12, 5)); // set the layout to 4 rows and 4 columns

		gameOverLabel.setHorizontalAlignment(JLabel.CENTER);
		gameOverLabel.setVerticalAlignment(JLabel.CENTER);
		gameOverLabel.setFont(new Font("Arial", Font.BOLD, 36));
		
		button.setHorizontalAlignment(JLabel.CENTER);
		button.setVerticalAlignment(JLabel.CENTER);
		button.setFont(new Font("Arial", Font.BOLD, 36));
		button.setSize(50, 10);
		
		gameOverPanel.setLayout(new BoxLayout(gameOverPanel, BoxLayout.PAGE_AXIS));
        
		gameOverPanel.setLayout(new BoxLayout(gameOverPanel, BoxLayout.PAGE_AXIS));
		gameOverPanel.add(Box.createVerticalGlue());
		gameOverPanel.add(gameOverLabel);
		long endTime = System.currentTimeMillis();
        long runTime = endTime - this.startTime;
        
        JLabel score = new JLabel("Score: " + runTime);
        score.setFont(new Font("Arial", Font.BOLD, 26));
		gameOverPanel.add(score);
        gameOverPanel.add(button);
        gameOverPanel.add(Box.createVerticalGlue());
        gameOverLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
        button.setAlignmentX(Component.CENTER_ALIGNMENT);
        score.setAlignmentX(Component.CENTER_ALIGNMENT);

        
        // Add glue to the left and right to center the components horizontally
        gameOverPanel.add(Box.createHorizontalGlue());

		
		button.addActionListener(new ActionListener() {
	         public void actionPerformed(ActionEvent e) {
	            gameOver = false;
	            System.exit(0);
	            //RestartGame();
	         }
	      });
		
		RecreateWindow();
	}
	
	public void RecreateWindow() {
		
        // create and add tiles to the panel
        for (int i = 0; i < matrix.length; i++) {
        	for(int x = 0; x < matrix[1].length; x++) {
        		//System.out.print(x + "" + i);
        		jPanelmatrix[i][x].setPreferredSize(new Dimension(60, 50));
            	jPanelmatrix[i][x].setBackground(Color.white); // alternate tile colors
            	if(matrix[i][x] == 1) {
            		jPanelmatrix[i][x].setBackground(Color.MAGENTA);
            	}
            	gameBoard.add(jPanelmatrix[i][x]);
        	}
        }
        gameWindow.add(gameBoard);
        gameWindow.pack();
	}
	
	public void actionPerformed(ActionEvent e) {
        if (e.getSource() == button) { // check if the button was clicked
        	//System.out.println("Restarting");
        	System.exit(0);
        }
    }
	
	public void RandomizeDrop() {
		Random random = new Random();
		int spawns = random.nextInt(4);
		
		for(int i = 0; i < spawns; i++) {
			//System.out.println("Spawning at " + random.nextInt(5));
			matrix[0][random.nextInt(5)] = 2;
		}
	}
	
	public void UpdateGame() {
		for (int i = matrix.length - 1; i > -1; i--) {
			for(int x = matrix[1].length - 1; x > -1; x--) {
				//*/
				//System.out.println();
				jPanelmatrix[i][x].setPreferredSize(new Dimension(60, 50)); // set the tile size to 50x50 pixels
				Color color = Color.white;
				//System.out.println(i);
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
				if(matrix[i][x] == 2) {
					color = Color.black;
					if(i == 11 && x == playerLocation) {
						gameOver = true;
						gameBoard.setVisible(false);
						//System.out.println("Game playing: " + !gameOver);
						gameWindow.add(gameOverPanel);
					}
					//System.out.print(" = Black");
					//This adds gravity to the block
					
					if(i <= 11 && !(i == 11 && x == playerLocation)) {
						//System.out.print("This is where it fell: " + x + ", " + i);
						coords.add(new Coord(i, x));
					}
					if(i == 0 && !(i == 11 && x == playerLocation)) {//This is to get rid of the block at the end
						//matrix[i][x] = 0;
						jPanelmatrix[i][x].setBackground(Color.white);
					}
				}
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
				jPanelmatrix[i][x].setBackground(color); // alternate tile colors
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
				gameBoard.add(jPanelmatrix[i][x]);
				//System.out.println();
			}
        }
		jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
		for(int i = 0; i < coords.size(); i++) {
			int x = coords.get(i).x + 1;
			int y = coords.get(i).y;
			Color color = Color.black;
			//System.out.println(x + "-------------------");
			
			if(x == 11) {
				//System.out.println(playerLocation + ", " + y);
				
				if(jPanelmatrix[11][playerLocation].getBackground() != Color.black && y == playerLocation) {
					
				}
				
				/*
				if(y == playerLocation && jPanelmatrix[x][y].getBackground() == Color.black) {
					System.out.println("Killed by: " + x + ", " + y);
					gameOver = true;
					gameBoard.setVisible(false);
					System.out.println("Game playing: " + !gameOver);
					gameWindow.add(gameOverPanel);
				}
				*/
			}
			
			if(x == 12) {
				jPanelmatrix[x - 1][y].setBackground(Color.white);
				matrix[x - 1][y] = 0;
			}else {
				matrix[x][y] = 2;
				matrix[x - 1][y] = 0;
				jPanelmatrix[x][y].setBackground(color);
			}
			
			jPanelmatrix[x - 1][y].setBackground(Color.white);
		}
		jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
	}
	
	@Override
	public void keyPressed(KeyEvent e) {
	    // handle key press event
	    int keyCode = e.getKeyCode();
	    //System.out.println("Key pressed: " + KeyEvent.getKeyText(keyCode));
	    if(keyCode == KeyEvent.VK_A) {
	        if(playerLocation > 0) {
	        	jPanelmatrix[11][playerLocation].setBackground(Color.white);
	        	playerLocation = playerLocation - 1;
	        	jPanelmatrix[11][playerLocation].setBackground(Color.magenta);
	        }
	    }
	    if(keyCode == KeyEvent.VK_D) {
	        if(playerLocation < 4) {
	        	jPanelmatrix[11][playerLocation].setBackground(Color.white);
	        	playerLocation = playerLocation + 1;
	        	jPanelmatrix[11][playerLocation].setBackground(Color.magenta);
	        }
	    }
	    //System.out.print(playerLocation);
	}


    @Override
    public void keyReleased(KeyEvent e) {
        // handle key release event
    }

    @Override
    public void keyTyped(KeyEvent e) {
        // handle key typed event
    }
	
    public void RestartGame() {
    	Random random = new Random();
		if(firstOpen) {
			CreateGameBoard();
		}else {
			RecreateWindow();
		}
		JFrameBuilder();
		while(!gameOver) {
			RandomizeDrop();
			for(int i = 0; i < random.nextInt(3) + 1; i++) {
				try {
				    // wait for 1 second (1000 milliseconds)
				    Thread.sleep((long) gameSpeed);
				} catch (InterruptedException e) {
				    e.printStackTrace();
				}
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
				UpdateGame();
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
			}
		}
    }
    
	public Falling_Game(){
		Random random = new Random();
		if(firstOpen) {
			CreateGameBoard();
		}else {
			RecreateWindow();
		}
		JFrameBuilder();
		while(!gameOver) {
			RandomizeDrop();
			for(int i = 0; i < random.nextInt(3) + 1; i++) {
				try {
				    // wait for 1 second (1000 milliseconds)
				    Thread.sleep((long) gameSpeed);
				} catch (InterruptedException e) {
				    e.printStackTrace();
				}
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
				UpdateGame();
				jPanelmatrix[11][playerLocation].setBackground(Color.MAGENTA);
				if(gameSpeed > 200) {
					gameSpeed = gameSpeed - 5;
					//System.out.println("GS: " + gameSpeed);
				}
			}
		}
	}
	
	public static void main(String[] args) {
        new Falling_Game();
    }
}

class Coord {
    int x;
    int y;

    public Coord(int x, int y) {
        this.x = x;
        this.y = y;
    }
}