Space Invaders DX/Parody Mode

As mentioned on the Walkthrough page, if you select this mode, the game shall start immediately; however, it is essentially the same as Normal Mode, but for that fact that it replaces the characters with those from nine older Taito Corporation games: The NewZealand Story (1988), The FairyLand Story (1985), Bubble Bobble (1986), Rainbow Islands (1987), Mizubaku Daibōken (1990), Arkanoid (1986), KiKi KaiKai (1986), Darius (1986), and Don Doko Don (1989). The main character from that seventh title, Sayo-Chan, also later went on to reappear as one of the first-player characters for Akkanvader.

Once you clear the ninth stage, the cycle will start over again, and repeat until you run out of lives (or the invaders make it to the bottom of the screen).