I love spy games, this one has to be one of the best ones.

Stealth Xcom. That about sums it all up though, I can't really point to any breakaway feature. For it's effectively simplified mechanics it sticks around far past it's welcome. That's the thing I would say drags it into the red. They took a 10 minute story and stretched it across many hours of gameplay that isn't sustainably interesting for that long. I remember lowering the difficulty on the last series of what should have been climactic missions not because it was too hard but because I just wanted to skip to the end, which was itself underwhelming.