Humble Double Fine Bundle now includes eight Amnesia Fortnight prototypes, documentary

The good folks at Humble Bundle added nine pieces of bonus content to the Humble Double Fine Bundle today, including eight prototypes that came out of the studio's well-known Amnesia Fortnight sessions.

The Humble Double Fine Bundle launched a week ago with a pay-what-you-want price for Psychonauts, Costume Quest and Stacking; those who pay more than the average will receive a copy of Brutal Legend as well, with all games available on Windows PC, Mac or Linux. Buyers also have the option of contributing $35 to become a "slacker backer" of Double Fine's Kickstarted adventure game, Broken Age, or $70 to receive a special Humble Double Fine Bundle T-shirt on top of everything else.

Amnesia Fortnight is Double Fine's name for its periodic internal game jams, in which small teams split off to build prototypes of their own games in two weeks. Here are the eight Amnesia Fortnight prototypes that are now a part of the Humble Double Fine Bundle: "Autonomous," "Black Lake," "Hack n' Slash," "Spacebase DF-9," "The White Birch," "Happy Song," "Brazen" and the original 2009 prototype for Costume Quest (image above).

Anybody who pays more than the average price for the package will receive the prototypes, which are only available on PC and can be redeemed on Steam. Double Fine is also throwing in Amnesia Fortnight 2012, a five-hour series in which 2 Player Productions — the studio behind the Broken Age making-of documentary — chronicled an Amnesia Fortnight session from last year.

The Humble Double Fine Bundle will only be available for one more week: The offer will expire at 6 p.m. EDT on May 21. You can buy it here.