Odd what's FF version? It worked fine for me on v32.0.2.
edit: It might be this suggested by Kripke:
"kripke 0 minutes ago | link
FF33.1.1 (on Archlinux) is working fine here. In addition to NoScript, you probably need to disable any extension that forbids cross-domain cookies as the relevant cookies are registered for https://ig-game.appspot.com/ and not a raw IP."
edit: It might be this suggested by Kripke:
"kripke 0 minutes ago | link
FF33.1.1 (on Archlinux) is working fine here. In addition to NoScript, you probably need to disable any extension that forbids cross-domain cookies as the relevant cookies are registered for https://ig-game.appspot.com/ and not a raw IP."