Firaxis is showing off the next member of XCOM: Enemy Unknown's alien menagerie: the Berserker. The XCOM organization's mission to defend Earth from interstellar invaders is going to be in serious jeopardy once these start showing up. The first video showing off the game stars the Berserker alongside the developers' explanation of XCOM's core gameplay. Normally, when confronted with an extraterrestrial menace, your first response as XCOM commander is to duck your team behind cover and set up firing angles to keep your soldiers from being too exposed to the enemy. That's a good...