The Fullbright Company yesterday launched an update adding the commentary mode. It offers more than an hour and a half of insights from the developers, voice actress Sarah Grayson, and composer Chris Remo, along with Heavens to Betsy lead singer Corin Tucker, whose band has several songs in the game. The update should download automatically, then to get the commentary simply hit the checkbox in the Modifiers menu when you start a new game.
This also just so happens to coincide with a 50% off sale, across the official site, Steam, and the Mac App Store. What a coincidence, eh? The soundtrack is also now available for purchase itself for a name-your-own-price minimum of $7.