Mileage will vary, as will the ride
The first Assassin's Creed ended with all the enigmatic hints at story direction that a conspiracy nut could ever hope for. Being partial to the odd secret history tale myself, I entered AC2 on a wave of anticipation of where the story may go. I also entered with certain reservations about the game play of the previous game and much of my expectations were based on seeing whether the game design issues of the previous title were addressed while keeping up the effective story telling of its predecessor.
An hour or two into AC2, it becomes evident that not many of the core mechanics of the game have changed. The developers instead attempted to break up the repetitive missions of the first game by building out the meta-game. There is always something to collect (paintings, weapons, feathers, video-clips) and some side-objective (assassination, race, fisticuffs) to complete, and if you are willing to let the game lead you by the nose you will get some mileage out of it. Your enjoyment of the game's many side-objectives will depend on your enjoyment of the core free-running, combat, and stealth mechanics as they are repeated in order to collect the goodies on offer.
Of the game-play mechanics, combat has received most of the attention. Different enemy types requiring different strategies to defeat. Fights are also typically larger in scale and I had less of a feeling that the AI was happily waiting to be killed off by counterattack after counterattack. Some exploitative strategies are still possible, but at least this sequel succeeds in not letting the player autopilot through combat encounters.
Stealth mechanics received less attention although the new protagonist, Ezio, is able to blend with a greater variety of crowds than (monk-groupie) Altair and direct allied groups (courtesans, thieves, mercenaries) to distract guards with varying levels of aggression. The AI unfortunately still creates some rather ridiculous scenarios wherein the player can be spotted on the top of a highly secure castle, break line of sight with a guard, and be forever forgotten. Renaissance era guards were apparently more fixated on the view than the flamboyantly dressed assassin attempting to gut their employer.
Ubisoft clearly attempted to one up the Altair character model, with something that would look more eye catching as a collectible figurine. The problem with this of course is that nothing sticks out more in AC2's game world than its protagonist "blending in". Another aspect where I felt the developer overreached, which ultimately coloured my enjoyment of the game, was the game's plot. I enjoyed the story far more when it was withholding its secrets from me than when it ultimately revealed what they were.
Ultimately, AC2 is a competent action adventure game that employs the same "RPG" game-play tropes as many of its contemporaries in an attempt to keep the player engaged. To its credit the story missions are more enjoyable and a player ploughing straight through should be in for a good romp. What will ultimately determine a player's enjoyment of the game however, are their feelings towards the story. Mine were as such that I'm putting this franchise on the backburner for a while.