If you enjoyed the strategic turn based combat of XCOM: Enemy Unknown but thought it needed more squids and robots, then look no further than XCOM: Enemy Within.
Enemy Within is Firaxis’s first expansion pack for the hit XCOM reboot and will add more enemy types, extra maps, and two new skill trees for your troops. Players may choose to enhance their loyal multi-cultural soldiers with advanced mech-technology or they can be genetically manipulated with a “newly discovered alien substance.” The latter option is likely what the game’s “Enemy Within” title refers to.
Check out the PAX trailer of XCOM: Enemy Within for some questionable medical procedures and awesome mech-battles.