Space Invaders

Nine lives:
Pause game play and press Right(3), Down, Circle, Left, Down.
Information in this section was contributed by megacortex.

Five shots:
Pause game play and press Down, Left, Circle, Down, Right(3).
Information in this section was contributed by megacortex.

Level select:
At the main menu, select either one or two players and press Circle (instead of X) to begin the game. A selection screen that allows any level, including planet Mercury with a new power up and an "Alien World" featuring the best background in the game.
Information in this section was contributed by PacManic.

Classic mode and credits:
Enable the "Level select" code, choose level 00, and complete it to unlock an ending, classic mode, and credits. Press Right when selecting then number of players to access classic mode. Enter the options screen to access the credits.
Information in this section was contributed by Pokemat151.

Information in this section was contributed by Pokemat151.

Alternately, successfully complete the game under the normal difficulty setting.

Maniacal difficulty:
Alternately, successfully complete the game under the expert difficulty setting.

Hint: Mercury level:
Successfully complete the game in expert mode. After defeating the Earth Boss, you will be transported to Mercury. The unique enemy is called Leecher. The Special Missile is fairly useful, called the Silo Attack, where missiles appear from the ground and fly straight up. Unlike the Vertical Burst, they only hit one alien on contact. The Boss is a easy if you have Double Shot. Meteors fall from the sky and take two hits. The more damage you take out, the faster the space rocks fall. Without Double Shot it is slightly more difficult, whereas missing a rock disables your next shot until the rocket leaves the screen or it hits something.
Information in this section was contributed by Stcar53474.

Hint: Alien Homeworld level:
This level is the deck of an arcade game. The unique ship is the Shifter. It will occasionally fly towards the screen a slightly, dodging your tank fire, then returning to the formation after a second. This is probably the third most dangerous enemy, as it fires three to five bullets in a single round. If you can get around it, it is easy. The Boss is one of the classic aliens you see in the background. He appears in a large form, then begins a small barrage of laser blasts, following the movement pattern of a normal alien. As he takes damage, he gets smaller, returns to the top of the screen, and gets noticeably faster in its movement. The laser blasts increase a great deal. If you do not have experience in firing on quickly moving targets, you will not survive this encounter. If you defeat this difficult enemy, you will unlock the "Maniacal" difficulty level. Everything follows expert mode, but your tank and your rockets move unbelievably fast. You also will automatically have double shot.
Information in this section was contributed by Stcar53474.

Strategy: by Kirk Israel
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