What is The Bureau: XCOM Declassified?

Originally, it was just XCOM. Then XCOM: Enemy Unknown came out, and everyone forgot about it. But the XCOM shooter never went away--it just changed. Now, it's something different. Something more unique. It's The Bureau: XCOM Declassified, and we've played a few hours of it. What do we think? What is it? Here's your answer.