A little over two months after Mighty No. 9's initial launch, the game is finally available to download on Mac and Linux. If you've been waiting for these versions, you can grab them on Steam. DRM-free versions are reportedly in the works, too, bound for Humble Bundle as "soon as they are ready."
Still no word yet on the 3DS and Vita versions, though. Keep on waitin'.
Source: Mighty No. 9 backer update