Don't know if this is a problem with documentation, the code or something else.

Important: the Drupal 7 version of Acquia Marina 7.x-1.x requires Fusion 7.x-1.x, and is not compatible with Fusion 7.x-2.x.

You can't get Fusion 7.x-1.x anymore, well not off the main page. The Fusion page only shows availability of 7.x-2.*. To get 7.x-1.x you need to dig down to the unlinked Release page.

Is there any plan to update Marina so that it's based on a non-alpha version of Fusion?