At first take it's got the kind of feel to it you get when listening to some of Queen's work such as "Somebody to Love" or "Bicycle Race" - it's rock n' roll no doubt, but it's influenced by genres which aren't always explored by 2 guitars, bass and drums.
The song's got a great thump behind it, some heavy descending power chords and a march-y feel that echoes the militaristic scenes the lyrics speak of (which, in an odd way remind me of Leo Tolstoy's Sevastopol in May ).
All-in-all, it's got me stoked to hear the rest of the album when it's released later this year...
Listen: Coldplay - Violet Hill
Related: Lest We Forget (contains excerpts from Tolstoy's Sevastopol in May)