Let's Go! is a quick sound effect that plays at the beginning of each stage in Lemmings. It was first heard in the Amiga version where it was a digital recording of someone's voice, increased in tempo to raise its pitch (think Alvin and the Chipmunks). However, since the game was ported to numerous devices incapable of playing digital audio, it was played as an instrumental two-note sound effect attempting to match the spoken words. It is unknown whose voice was used for the recording.
The original Amiga version of this tune is a digital recording of someone saying the phrase "Let's Go!".
The game's music arranger, Tony Williams no doubt made the two note equivalent of the "Let's Go!" interjection. It is played at the start of each new stage.
Lemmings & Oh No! More Lemmings (PS1)
In the PlayStation version, Let's Go! is a lower-pitched digital recording of someone's voice.
Practically the same as the Amiga version with a digital recording of someone saying the phrase "Let's Go!", but in lower pitch.