I'm wondering about the storyline however. Is it true that Double Agent, Conviction, and Blacklist connect to one another in terms of story? Should I just start with Double Agent first? --- Alright you primitive screwheads, listen up. See this? This is my BOOMSTICK!
You're probably better off starting on Blacklist, the story has continuity errors if you play the previous games and then jump into this one, especially when it comes to Sam and his whole appearance. --- Now the story of a family whose future was abruptly cancelled, and the one fan who had no desire, but for it to keep going. It's S4 of Arrested Development!
There is one major character in the game that whose reveal is very much dependent on having played Conviction Kobin and another supporting character who is the same boat. Vic. Also quite a few of the character interactions with Grim hold more depth if you know her and Sam's past history.
You could certainly get by without having played Conviction and the others but I would try to get Conviction under your belt at least. (However one of the biggest emotional moments in Conviction also depends on having played Double Agent). Good game, well worth playing. --- I suppose you could never explain to the most ingenious mollusk that such a creature as a whale existed-Emerson