When it comes to expanding upon on an original concept, Firaxis is not averse to getting its hands dirty. After spending the last couple of years reworking, refining and enhancing key elements of Civilization 5, the developer has now slapped XCOM: Enemy Unknown on the operating table, rolled up its sleeves and poked at the innards of what was already one of the best strategy games around.
As a result, XCOM: Enemy Within benefits from the kind of base-level modification that typifies the genetically enhanced soldiers and mechanised brutes that serve as its own headline additions. It's not perfect, but Firaxis has enhanced XCOM's core to create an unquestionable improvement on what went before.
These modifications start by smoothing a number of minor imperfections in the original formula. There's a host of new maps to drastically lessen the need to reuse environments, there are medals available to bestow upon worthy soldiers and there's a much needed - if still too basic - reworking of Enemy Unknown's clunky inventory system, making it easier to redistribute equipment.