It can be thought of as a vertical presentation of the Volcano stage on the original Gradius. Enemy ships rise from Hatches of some form far down below, and rise quickly to attack the Vic Viper, while some enemies scale the sides of the area to shoot at the Vic Viper. The Vic Viper faces the Fortress Valis.
In Life Force, as usual, organic backgrounds are added, though strangely, after the pre-stage section of stage 4, the background changes to the mountainous backgrounds in which the enemies rise from the Hatches, unchanged from the original Salamander, and a lot of the enemies, though re-colored to green for some reason, retain their mechanical designs, and even the Center Core goes unchanged. In the NES version, the boss is Tetran instead.