|“||The fact that a piece of music containing only three notes has remained with everyone for so long is really surprising to me. I think it’s because that even before the music was in place, the game world of Metroid was fascinating.||„|
Title (Metroid) begins with a repeating six-note motif, a tense and mysterious high-pitched melody playing over low droning. It then transitions to a lighter section reminiscent of a lullaby, with high notes like the twinkling of stars. The song builds to a climactic series of arpeggios before resolving with the same low droning heard at the beginning. In the original game, it does not loop back to the beginning, instead repeatedly playing the low drone. It can be heard here: 
This song is one of several tracks that sound different between the Nintendo Entertainment System and Famicom Disk System versions of Metroid, with the latter having higher-quality instrument samples. The FDS version is included in Super Metroid: Sound in Action, named Title (タイトル), and in Game Sound Museum ~ Famicom Edition ~ 12 Metroid, named Title BGM (タイトル BGM). A short version of the FDS version of the theme appears in Animal Crossing: Wild World and City Folk, when the Villager touches their Metroid capsule item. The full theme is heard in Nintendo Land, when selecting a mission from the Metroid Blast gate. It can be heard here: 
Title (Metroid) has been performed live in concert as part of the Metroid medley in Video Games Live. This arrangement is very faithful to the original in tone, but is considerably shortened in length.
Title (Metroid) was orchestrated again as part of the Metroid medley in PLAY! A Video Game Symphony in 2011. This version sounds darker and more dramatic than usual, though still manages to sound heroic.
A synthesized arrangement by Tanaka is present on his Kid Icarus / Metroid Original Soundtrack Orchestra Version single, referred to as Title Music (タイトル音楽). It can be heard here: 
In Captain N: The Game Master, the opening notes can briefly be heard in the episode Kevin in Videoland when Princess Lana is shown held prisoner in Metroid. A longer remix is heard during the episode Metroid Sweet Metroid when Mother Brain pretends to be defeated after losing her Power Flowers. It is heavily synthesized, giving it a strong 80s vibe.
In Super Smash Bros. Melee, Title (Metroid) is partially remixed in Brinstar (Melee), a medley of songs from the original game. Here, the melody sounds very electronic, like the beeping of technology. Brinstar (Melee) is also featured in all later games in the Super Smash Bros. series.
Smashing... Live!, a live orchestral performance of the Melee soundtrack, featured an arrangement of Brinstar Depths (Melee) and Brinstar (Melee) titled Depth of Brinstar. An orchestrated version of Title (Metroid) is heard during the Brinstar (Melee) segment, with low brass performing the droning and high woodwinds playing the melody.
Title (Metroid) is fully remixed in the original game's remake, Metroid: Zero Mission. This version moves the six-note motif to the end of the song, and then loops back to the beginning of the lighter section. An abridged version that only consists of the droning and six-note motif is heard in the Samus Data Screen and Options menu. Both versions are included in the Sound Test, the former as number 03 and the latter as 01. It can be heard here: 
A remix of the full theme appears in Super Smash Bros. for Wii U on the Pyrosphere. Composed by Kohta Takahashi from Bandai Namco, this version incorporates part of Samus Aran's Appearance Fanfare at the beginning and the ending theme from Metroid at the end. This version of the song is included on the blue CD of the Smashing Soundtrack that was a Club Nintendo bonus for registering the Nintendo 3DS and Wii U games. It can be heard here: 
The Wii U Title (Metroid) remix returns in Super Smash Bros. Ultimate, where its name has been changed to Title Theme - Metroid. It can now be played on any stage from the Metroid series.
- The opening six notes of Title (Metroid) would be remixed in almost every Metroid game afterward, becoming a main theme for the series itself.