That would be more than enough space for basically any android game. I think there's two versions of the same version of the app. Have you tried both?
Well, last idea I have is, did you give the file viewing application permission to install unknown applications. This isn't necessary if you're just using the standard device storage navigator. I doubt that's the issue, but the only other options are issues between the application and your device. If that's the case, then try a different device if possible, and hope the developer sees this if not.