| 
                     Prototype
                            Differences  
                   | 
                
                
                  | The game starts automatically | 
                
                
                  There fireballs do not make
                      a sound when launched 
                     | 
                
                
                  Tune after destroying
                        the Death Star is different and very short 
                       | 
                
                
                  You do not zoom in on
                        the Death Star after the Tie Fighter wave 
                       | 
                
                
                  If your shields go past zero you do not die, they
                      just stay at zero 
                     | 
                
                
                  The screen flashes grey instead of red when you
                      get hit by a fire ball 
                     | 
                
                
                  | When playing the game on hard (left difficulty switch
                      on A), Darth Vader's Tie Fighter doesn't appear until the
                      second wave.  | 
                
                
                  | The Color/B&W switch freezes everything on
                      screen.  Fireballs will still move and damage you
                      however. | 
                
                
                  The towers do not get larger as they get closer to
                      your ship 
                     | 
                
                
                  Once you hit a tower most of the other towers will
                      also appear destroyed 
                     | 
                
                
                  | There is no flashing when Death Star is
                        destroyed | 
                
                
                  | The crosshairs flicker a bit. |