While the "Evolved" version found in the previous XBLA release was just HD window dressing for the same game, this adds new elements -- like troops, who will gather powerups and fight each other on the screen even as you're trying to bounce fireballs into enemy castle walls. So it's kind of a strategy game now. It also includes multiple local and online multiplayer moves.
Honestly, if we're going to see one game remade frequently, we're happy it's this one. Now if only our modern consoles had paddle controllers.