If there's one thing this week has proved, it's that everything changes. Fable is now a ludicrously cuddly four-player co-op adventure for Xbox Live Arcade. Forza Horizon appears to be a pitch to the festival crowd, rather than automobile anoraks. Peter Molyneux has announced his departure from Lionhead and Microsoft. And Halo 4? For all its Spartan armour, Warthogs and Battle Rifles, 343's long-unseen project isn't the same 30 seconds of fun. Combat is "faster, visceral and more intense", there's a brand new enemy on the way, and the HUD has been upgraded to provide a constant flow of match data.