Metroid Detector

A nearby Metroid detected in Samus Returns

The Metroid Detector is located on the bottom right corner of the HUD in Metroid II.

The Metroid Detector, also known as Metroid Radar or Metroid meter, is a technology exclusive to Metroid II: Return of Samus and its remake Metroid: Samus Returns. It appears as a small Metroid larva in the bottom right corner of the screen along with a number next to it, indicating the number of Metroids remaining on planet SR388.

Functionality

Each time Samus kills a member of their species in Metroid II, the number will scramble for a few seconds before it decreases by one, while in Samus Returns this number will simply tick down by one. Whenever Metroid II is paused, the tiny Metroid image on the Detector is replaced with an "L" and the number is reduced: this change of information serves to indicate how many Metroids are left in the immediate area Samus is located in instead of the entire global population. Samus Returns features a separate counter for Metroids in the area, from the tally of those on the planet.

In the remake, the Detector will begin beeping when a Metroid is nearby, while the number and image of the creature will turn green, yellow or red. Its beeping frequency and color will change depending on how close Samus is to the Metroid. When she finally confronts it, the Detector's noise will cease and stay at a constant red color. The beeping is a single sound, played repeatedly. It can be heard below.

Metroid count

By default, the number on the meter is 39 (Return of Samus) and 40 (Samus Returns) Metroids. However, once Samus has reduced this number to 1 (unbeknownst to her, representing the Queen Metroid) and crosses the first tunnel with the Metroid Egg in Area 8, the meter will coincidentally and suddenly increase up to nine in Metroid II and eleven in Samus Returns, indicating the eight and ten Metroid larvae in the respective game. In the remake, this occurs during a cutscene when Samus emerges from the tunnel and her Detector beeps erratically as the Metroid larvae's signals are picked up. This event in both games intend to imply the existence of a yet-to-be-seen creature propagating the species through egg-laying. By the end of Samus' mission on SR388, the Detector will have signaled on its meter number a total of 47 and 50 Metroids in Metroid II and Samus Returns, respectively. Curiously, both games' Detectors will not acknowledge the presence of the Infant Metroid found by Samus, leaving the meter number at zero after the Queen is killed.

Chozo Seals

Chozo Seals are a complement to the Detector, as the former specifically indicate the number of Metroids within the vicinity rather than the entire planet; while they may not show the exact location of a Metroid, they can reveal on Samus' Map Screen the position of discarded husks belonging to living Metroids, thus aiding the Detector in tracking the creatures found nearby. The Metroid Radar can be further enhanced by the Metroid Marker, which is usable if the Metroid amiibo has been scanned during gameplay.

Official data

Metroid II: Return of Samus manual

METROID DETECTOR

The number of Metroids detected on the planet.

This detector can also show other information about Metroids.

Metroid II: Return of Samus Virtual Console manual

Metroid detector

"The number of Metroids left on the planet."

Super Game Boy Player's Guide

GET 'EM ALL

"Samus' Metroid Meter will show the exact number of Metroids in any given area. Remember that every last Metroid must be wiped out!"

Metroid.com (Metroid: Samus Returns)

Metroid Radar

"A convenient tracker located on the bottom of your map that lets you know if there’s a Metroid near you, and how many you have left to kill."

Metroid: Samus Returns manual

Metroid Radar

"Displays the number of Metroids on the planet. A reaction occurs when a Metroid is nearby."

Metroid: Samus Returns Official Guide

HOW TO PLAY - BASICS - THE TOUCHSCREEN (p. 7)

METROID RADAR

"The Metroid icon on the right side of the bottom-middle panel is your Metroid Radar. It displays the total remaining Metroids on the planet and signals if one is near. If that icon begins flashing, a Metroid is close by."

Trivia

• As previously stated, when the last Metroid on SR388 is born, the Detector's meter does not rise up to one. Samus Returns retains this detail from the original Metroid II, confirming that it is an intentional effect and not an oversight. No explanation is given in either game, though it can be deduced that the energy which emanates from Infant Metroids is simply too small to be picked up by the Detector in comparison to all other, larger Metroid forms on the planet.
  • The sudden detection of numerous Metroid larvae in Area 8 was likely caused by the creatures being Infant Metroids for some time and remaining undetected until they all simultaneously grew into the larva stage.
• The Metroid Detector is akin to the Motion Trackers used by characters in the Alien films to track the movements of the titular creatures, also known as Xenomorphs. This similarity is further highlighted in Samus Returns, where it emits a beeping sound of varying frequency depending on how close Samus is to a Metroid, similar to the motion trackers and their detection of Xenomorphs.