Abadox

Abadox is a video game for the NES, subtitled The Deadly Inner War. In it, the player (as "Second Lieutenant Nazal") battles an alien organism named Parasitis that engulfed and digested the entire planet "Abadox", and assumed its shape. He must fly into the alien's body in an attempt to rescue the swallowed Princess Maria. The gameplay can be considered somewhat similar to R-Type as much emphasis is placed on memorization and avoiding not only enemies but also the equally hazardous environments. This is also true for the vertically scrolling levels. The gameplay largely follows the conventions of scrolling shooters of the time. The player shoots enemies, takes one hit to get killed and acquires power-ups, such as more powerful weapons and speed power-ups. The speed power-ups are especially important, since Nazal moves very slowly without them. This can create problems if the player dies - since the speed is reset, on some levels it can be near impossible to adequately dodge enemies... full article at wikipedia