From C1 wesbite: "Moment of Truth is a sequel to the popular stealth action title Death to Spies."
And I was corrected on these forums for calling it a addon when its a sequel. Same thing happened with Deadly Dozen, the sequel Deadly Dozen: Pacific Theater is the second game. I asked the developers directly about that one. When they game the game engine significantly I believe they like to call it a "proper sequel", but it would be nice for Haggard Games to confirm
