XCOM has a nice little surprise for those willing to go without achievements for the game: superhero "cheat" characters who, in addition to being maxxed out killing machines, are also famous video game developers.
Both Civilization creator Sid Meier and BioShock frontman Ken Levine are available, and accessible in about the simplest way possible: just go to your squad screen and change a soldier's name to... Sid Meier or Ken Levine. It's that easy. You can see the "cheat" in action in the video above.
This obviously works just fine on the PC version, but I'm not too sure about the console editions. There are also two more "heroes" available who aren't famous developers, one comics writer Joe Kelly, the other being Let's Play star Otto Zander.