This download is just the custom story of La Caza and not the full conversion.
This download will allow any and all users that own Amnesia: The Dark Descent to play La Caza. The full conversion seems to work for a majority of folks, especially the Steam version.
Though if you are having issues with the full conversion mod, this is the full story without the custom Menu and Pre-Menu. Also, some Mac users were not able to use the full conversion, this custom story is for you!
1.1 was missing the skybox, there is no difference from the full conversion 1.1