Last year's strategy standout, XCOM: Enemy Unknown, gets a makeover with a good old-fashioned expansion pack for PC, also available as a "Commander's Edition" bundle on consoles. The already brilliant original game, which saw players take command of Earth's defence against an alien invasion, is tweaked here almost to perfection, packing a slew of new elements. Enemy Within also draws out the game's narrative themes, emphasising the moral tension engendered by the cybernetic development of your ragtag squad of commandos as they desperately try to stave off fearsome extraterrestrials.

XCOM's brilliance really lies in how it uses narrative to make game features understandable. All the new elements here complicate decision-making in a very intuitive way, so it's never overwhelming. Instead, Enemy Within revitalises the game for old players and makes it better for new ones, turning an already great game into a masterpiece.