On http://www.ftlgame.com/ one can buy a DRM free version of FTL plus Steam key for $10 (the Steam-alone version costs €10 = $13 in Europe), while on gog.com it's available for $9.99 (without Steam). Is the ftlgame.com DRM free version a gog.com gift key (thus including the gog.com bonuses), or "only" a DRM free exe?
The version sold on FTLgame.com is not a GOG key, it's a standalone download for each platform. It is the same purchase/download system used by the Humble Indie Bundles, if you have bought any of those. You get totally unrestricted downloads for each platform, and a button to fetch a Steam key, but none of the GOG.com extras.
A blog post on the official blog summarizes the different ways to buy: http://www.ftlgame.com/?p=378