Outcome

"Dream within a Dream" (Hans Zimmer) features a thrilling introduction. 0:00-0:02 introduces a basic rhythmic beat that crescendos and expands in register to higher pitches. At 0:03, the rhythm adds more beats, and the melody contains unresolved harmony (every other 4 measures has a non-tonic chord for suspense). Finally, from 0:27-0:34, an ominous foghorn-like melody penetrates the air (with a deep timbre and crescendoing volume to stand out). All these effects build suspense and create a tension that is added to when the main melody arrives at 0:46.

"Never Let Me Go" (Florence and the Machine) follows the song structure of most pop songs:

0:00-0:04 Introduction: The piece starts off with an interesting, almost static sound effect. It's distinct enough from the song that it may just be for effect in the music video.
0:04-0:41 First verse: This verse is the simplest, as it introduces the piece. With only vocals, a basic piano accompaniment, and reverb, it sets up the dreamy underwater atmosphere.
0:41-0:47 Pre-chorus: The dreamy "never let me go"s lead in to the chorus, a local climax.
0:47-1:14 Chorus: The main melody is present in this refrain, slightly louder than the verse.
1:14-1:43 Second verse: Building off the first verse, a drum beat and more harmony is added.
1:43-2:09 Chorus: A repeat of the first chorus, but harmony voices are added after the first two solo lines.
2:09-2:36 Bridge: This change in melody adds variation to the song and contrasts the verses.
2:36-3:01 Third verse: Going back to voice and accompaniment, the piece becomes contemplative.
3:01-3:56 Chorus: The final chorus has the solo sing over repeated "never let me go"s. With multiple overlays of music and voice, this is the climax of the piece.
3:56-4:28 Conclusion: The voices finish singing, and the instruments end the melodic idea and slowly fade out.