My Love for the FEZ soundtrack has been mentioned many times on this blog and it deserves to.
Disasterpeace managed to create a soundtrack that both suits the game perfectly but also stands the test of time for its own with instrumentation and melodies that manage to excel for remixing.
Solar Fields did this as part of Side F of the Fez Remix album for the track Puzzle and turned an uplifting and bouncy track into something slower and allot darker. I really like the sence of power throughout this track as it slowly ebbs and flows to its conclusion: