XCOM: Enemy Within - Preview @ Polygon
Polygon has another preview of XCOM: Enemy Within talking about the game balance.
The introduction of the meld resource and its limited availability inwill make the game more aggressive as players rush to claim it before it self-destructs, according to lead designer, Ananda Gupta.
During a hands-on demo with the game at PAX Prime 2013, we played through a level of Enemy Within where we had to collect meld and fight the alien invaders at the same time. Meld, which is a new resource that has been added to both new and old maps, is used to create mecs and to give soldiers genetic mutation (g-mod) abilities. The introduction of meld means that players don't need to dig into their other resources in order to create mecs and g-mods, allowing them to allocate resources like alloys to other projects.
Information aboutXCOM: Enemy Within
SP/MP: Single + MP