1. The Linux binaries on the new site are a tar.gz.gz, making `tar xf filename` fail, and besides that inconvenience, is probably a packaging error. You might want to fix that.
2. The OpenFL provided Haxe installer is broken, because it tried to download http://haxe.org/file/haxe-3.1.3-linux64.tar.gz, which is gone. Please either fix the OpenFL installer or make sure download links are backwards compatible by adding a redirect. (I'm assuming both projects are run by the same community)
I worked around problem #2 by modifying the installer script to use old.haxe.org, since the binaries on the new site are harder to use because of problem #1. But this could definitely dissuade newcomers to Haxe, despite all of its qualities (which, in my opinion, are many!)