Should've been declassified
This is a rushed disaster in the franchise, serving as an interquel between Call of Duty: Black Ops and Call of Duty: Black Ops II. It should be noted that this was also released on the same day as Black Ops II, which obviously meant that they had two of their own games competing against each other. It's very doubtful that this helped sales. Of course the fact that it was released simultaneously with Black Ops II doesn't really give you anything good other than a collector's item. But even for the standards, this is no excuse for something abysmal and rushed.
The cutscenes and in-game graphics look pretty good as far as handheld games go and are decent by Vita standards, and multiplayer can be enjoyable, but there is no Zombies mode which is disappointing, and the small multiplayer maps make spawn trapping common. Nuketown (or "Nukehouse" in this game) is literally cut in half, leaving only the yellow house and area around it to play. Worse still, the network mode is not reliable. Even the touch based controls make it hard to play.
The enemy AI is very poor. For instance, enemies tend to take cover behind explosive barrels. Also, many, many glitches. The most common is enemies getting stuck in random locations.
In fact almost all of the assets are reused from Black Ops 1 and 2, some are just slightly changed. E.g. Nicaraguan Sandinistas and Contras are the same Cuban Tropas, with the only difference being that they wear balaclavas, and they also have no distinguishing differences between each other; Rogue Mujahideen in the mission Escort Service reuse the models of OpFor soldiers from Modern Warfare. The worst offender is Raul Menendez's father, Jose Luiz, who looks like a mustached young Raul with shorter hair, despite the fact that he had a much different and elder appearance.
Give this one a miss and play Black Ops II--you'll be happy you did.