XCOM: Enemy Unknown takes you through a handful of interesting locations. Areas where missions take place are very dark and atmospheric; the fog of war will keep you in a perpetual state of unease. This goes a long way towards the inevitable relief you will feel when your troops are safe back at Headquarters. Aliens may fit the stereotypical "gray men" we've come to expect from pulp science fiction. The most basic types are shorter humanoids with large heads and giant eyes; they look just plain evil. As more and more complex enemy types enter the fray, you will learn not to underestimate them -- even if they don't look like much of a threat.
When an alien spots you, it does so accompanied with a distinctly eerie audio flourish -- a handful of discordant piano keys are twiddled out as they scamper into action. The sound effects are great on both sides of the action; alien weapons sound superior and deadly, while human weapons sound like they were designed to inflict pain and death. Voice acting alternates between corny and genuinely scary; the gung-ho attitude of your combatants is something right out of Aliens, but the game can get genuinely creepy.
