This is almost assuredly an issue with the site itself. Gamestop release dates are notoriously inaccurate, especially for products that aren't in beta, and can change several times over the course of a game's development. In many cases, they're estimates or guesses.
Never trust a Gamestop release date without independent confirmation elsewhere.
I know you're excited about End of Nations... God knows, I am too. But you might want to pick up something else in the meantime. Perhaps Dota 2 or League of Legends? Get involved in the community for another game while you're waiting for more End of Nations news.
I think I saw somewhere that you're planning on making
EON your primary title when it comes out. I can sympathize with that, I am as well! But I'd go insane if I did nothing but check the
EON forums again and again with no news. Seriously, learn MOBAs. They're very complex with a lot of moving parts, and by the time you learn the genre well, we'll probably be swimming in
EON updates.