Enable the "Cheat mode" code and start a mission. If your shield gets destroyed and smoke start coming out from the aircraft, press BACKSPACE. Your shield will be restored, but your level will also be cleared. When you came back to your post you will have no money remaining.
Start the game with the rap record demo command to record your game play. Start the game with the rap play demo command to play back your recorded demo. Note: This is only available on certain versions of the game.
Before you load the game, enter the game's directory and type SET S_HOST=CASTLE (case-sensitive) at the command line. Then, type rap to load the game. All weapons, $900,000, unlimited health, and five bombs will be available when game play starts.
Enable the "Cheat mode" code and start a mission, then press ESC and select "Yes" to abort the mission. Enter the mission again and abort, but select "No" this time. The game will end the mission and return to the hangar screen. Play the mission to jump to the next mission.
-Set the system date to March 12th, May 16th, August 28th, or October 2nd to fight cows, monkeys and other animals. Another way is to turn on all the switches at the bottom of the episode selecttion screen and darken the button. A sound will confirm correct code entry.
-Play a mission that has a weapon other than the standard lasers as equipment. Abort the mission and sell the weapon. Repeat this process to earn an unlimited amount of money.
-Choose "New Mission" and Rookie mode. Play four levels of Bravo Sector. In the fifth level, you will find a "dumb fire missile". Collect it and press ESC. Exit the mission. Your plane should have landed successfully. Go to the supply room. You will see the "dumb fire missile" that was collected. Sell it to collect money. Repeat this as many times as desired. You can use the money later to purchase the "twin laser" and complete levels easily. Note: This trick will not work if you already have five or more mega bombs or shields.