==CODES==

-Harder Mode, Extended Mode, Score Attack and Exit game-
Insert following commands on the title screen when inserting a credit to get Harder Mode, Extended 
Mode and Time Attack. To exit game, enter command while playing.
+--------------------------------------------------------------------+------------------------------------------------------------+
| Effect                                                             | Code                                                       |
+--------------------------------------------------------------------+------------------------------------------------------------+
| Exit game: quits current game.                                     | Up, Up, Down, Down, Left, Right, Left, Right, A, B, Start. |
| Extended Mode: 2nd loop with increased difficulty.                 | Press Down when inserting credit.                          |
| Harder Mode: destroyed enemies leave Suicide Bullets.              | Press Up when inserting credit.                            |
| Time Attack: 5 minute time attack on stage 6 with infinite lives.  | Press A+B when inserting credit                            |
| Gain 1 minute for every 1 million points.                          |                                                            |
+--------------------------------------------------------------------+------------------------------------------------------------+