Stage 4 begins on Planet Zebes: Brinstar. Samus Aran is the opponent on this stage. When she is defeated, a cutscene begins, with the stage shaking and rumbling while bits of debris fall from the ceiling (similar to Ceres at the beginning of Super Metroid), along with a loud warning klaxon and "DANGER!" flashing on the screen. The character in use then begins an escape through a Metroid series-styled vertical shaft. An an added touch, the shaft resembles the tall vertical shaft from Super Metroid's Crateria that leads to Mother Brain's old, ruined chamber in Tourian that is climbed once again while escaping at the end of the game. The platforms begin as small floating platforms, then the character in use jumps through a floor and up two parts of the rock wall sticking into the shaft. The platforms then become smaller and harder to land on, before reaching a metal shaft and two jump-through floors. A final floor leads into a room with an elevator very similar to the one in the Ceres Space Colony at the beginning of Super Metroid, although a Yellow Blast Shield exists above the platform (which did occur in one Crateria elevator). When the elevator is jumped onto, the stage is won. A cutscene shows Zebes exploding similar to Super Metroid (though this time much faster), then pans over and zooms in on the next stage, Pop Star, from the Kirby series.
Note that there is a forty second time limit to escape. If time runs out before the character in use reaches the top, the game continues as normal but the character in use loses one stock life (if said stock was the last one, it is game over). There are no enemies in the shaft, but landing the jumps on the small platforms may be tricky for some characters, along with the distance between them.
A Trophy will always appear in the shaft, but its location is random. Most of the time it can be found on one of the rock ledges, on a platform just below the double floors, or in the top room on either side of the elevator.
A Blue Door is seen at the bottom of the shaft, to the right of the starting point, but it cannot be opened, and is merely for decoration, and as a platform.
- By hacking, this stage is playable in Vs. Mode, though touching the elevator may cause undersirable effects.
- The beta version of this stage had the message "GO AHEAD" in the background instead of "CODE RED".