Power Up Cavern

The Power Up Cavern is a large room in Metroid II: Return of Samus and Metroid: Samus Returns.

Description
Located in Area 1, the Power Up Cavern is the first in a series of large dome-like caverns that Samus Aran explores during her mission to exterminate the Metroids.

The most notable feature of the Power Up Cavern is that it houses the ruins of a Chozo temple, which Samus can explore to obtain numerous power-ups. There are three different entrances to the ruins.

Additionally, the right side of the Power Up Cavern branches off into a pair of caves, one of which leads to the Spider Ball. A Metroid Husk can be found in the Power Up Cavern near the entrance to these caves, hinting that one of them is inhabited by an Alpha Metroid.

The roof of the Power Up Cavern features a Missile Battery and Big Energy Ball (Return of Samus) or an Ammo Recharge Station and Energy Recharge Station (Samus Returns), allowing Samus to quickly replenish her ammo and energy when needed.

Return of Samus
The Power Up Cavern is largely populated by Chute Leeches and Gulluggs. The Chute Leeches lie on the surface of the Chozo ruins, while Gulluggs circle around in the air to make Spider Ball navigation tricky.

Like the other dome caverns, the Power Up Cavern roof can be bombed in a few places, revealing hidden tunnels. However, none of these tunnels contain anything.

Interestingly, the right entrance to the Chozo ruins features a bridge over water, with some bushes growing out. Samus cannot go underneath the bridge, making these details purely aesthetic.

Samus Returns
In Samus Returns, the background has been updated with a lot more detail. Green light (presumably from the Surface) can be seen pouring in through the cavern roof. The rocky cavern is home to enormous pyramids and bridges left behind by the Chozo civilization, and newly-added details on the exterior of the Area 1 ruins suggest that the particular temple that Samus explores is just one of these many pyramids.

A Save Station is now located near the Metroid Husk on the right side of the Power Up Cavern. Perhaps as a reference to the bushes from the original, the right entrance of the Chozo temple and some of the nearby background bridge structures are noticeably overgrown with large vines.

Return of Samus

 * 18 Chute Leeches
 * 10 Gulluggs

Samus Returns

 * 1 Bugfly swarm (non-hostile)
 * 3 Electric Moheeks
 * 3 Gravitts
 * 10 Gulluggs
 * 5 Hornoads

Items

 * Missile Tank
 * In Samus Returns, Samus must ascend to the roof of the Chozo ruins. Underneath the left platform with an Electric Moheek, Samus can bomb the floor to reveal the Missile Tank.


 * Missile Tank
 * In Samus Returns, the roof of the Power Up Cavern contains a small cave populated by Gravitts. Samus must use bombs and missiles to clear a path to a Missile Tank.


 * Missile Tank
 * In Samus Returns, Samus can easily obtain a Missile Tank by simply using the Spider Ball on the wall next to the Save Station.