The definite aim toward a murkier, moodier Depeche in singles terms happened here -- with its descending keyboard chords, low bell sounds, and darker overall feeling, combined with Gahan's delivery of a wracked Gore lyric matched by haunting background vocals, "Leave in Silence" points toward where Depeche would end up.
As for the two alternate mixes of the track collected on the CD version, the "Longer" mix is just that and as a result will be mostly of interest to the hardcore fan, not being a notable revamp in any way beyond a few extended stripped-down parts here and there.
The "Quieter" version, in contrast, is indeed that, with most percussion absent while the gentle chime melody takes the lead throughout, the vocals mixed lower in comparison.
It's a low-key but successful revision.
Meanwhile, A Broken Frame album track "My Secret Garden" surfaces in two different versions as well, both instrumental.
The initial "Excerpts From: My Secret Garden" speeds up the overall pace and generally makes the song a bit of a brighter all-around affair.
"Further Excerpts" continues the basic theme and atmosphere with little variation, outside of an extended bass-heavy section toward the end.