emerge -f beryl only downloads the files, if you want to compile and install beryl you have to run it without -f
I see on my 3.4 system it wants to downgrade a couple of packages.
Try it and see for heaven's sake.
I have been using Gentoo for 4 years. I can assure you I know how emerge -f works. I just did it such I have the files downloaded and ready to be compiled. As I told you before the problem is that
might not be enough. So I really do not want to mess my system as I did in the past, trying to install beryl from Gentoo. When Beryl is already installed you can do that. This is because some configuration files regarding its plugins are taken care by Sabayon developers so in that case emerge beryl justs updates the binary files. In my case where Beryl is not pre-installed I cannot do that because simply there is no guarantee that it will work. Take a look at this and you will understand what I mean: