A post on the Wolfire blog yesterday announced that the source code for Aquaria has now been released. Aquaria, an action-adventure, underwater sidescroller from Bit Blot, was part of the Humble Indie Bundle, which was so successful that the developers of four games pledged to release them as open source. This marks the final release, following Lugaru, Gish, and Penumbra: Overture. The source code is available from a Mercurial repository.