Steel Empire

On the Ship Selection screen, press C, A, C, A, Start, B. You will hear a chime, and when you start the game you'll have 99 bombs!

On the Options screen, set Difficulty to HARD, Ships to 3, Continues to 2, and Sound to 77. While playing, you can press B on Controller Two for level 20 firepower!

To pick any level, enter the Options screen. Now select the following sound tests: 1, 1, 9, 2, 2. A "Round" entry will appear in the options menu.