Not that it needs defending as such, but some people harp on it as a fairly average stop gap between Brotherhood and what will become Assassin's Creed III. I'll admit, on my first run through of this game (which I only completed about a month ago) I was not really feeling it, the reason being that I had been taken in by the talk of it being a disappointing follow up to the great game that was Brotherhood. This is a fair complaint, and it is no ones fault but my own for having my expectations of the game lowered before I even began to play it and my cynical look on the game from the outset colouring my impression for the entire duration. However after finishing the game I realised that I did not let myself be taken in as I would have if I would have bought the game at launch and so may of had a different opinion.
In the month following this I proceeded to replay all the previous Assassin's Creed console games as a sort of preparation for AC3. Between the AC1 to AC:B my overwhelming opinion was that the games clearly get better with each iteration, AC2 far surpasses AC1 in my humble opinion, both in minor gameplay tweaks (such as Ezio's faster climbing speed) as well as storytelling (some people would criticise it for being more linear, but as a result I found Ezio's story more compelling as a tale and also Ezio as a character more than Altair), the one place where I felt it did not improve was graphically bizarrely, but this is an incredibly minor gripe as the quality of the rest of the game was at such a high level. AC:B again made strides in all these areas and is probably my favourite game in the series so far, despite my feelings that Cesare Borgia is a less compelling villain than his predecessor. In terms of story I have to stress I'm talking about events that take place purely inside the Animus, as everything that happens outside of it is so bat shit crazy that I'd rather finish the whole series before commenting on it.
Now for Assassin's Creed: Revelations, I just finished it again yesterday and have to say on a second run through I was much more impressed than I had been the first time, though there are still some gripes I would like to express. As far as the good points go, I have several; for a start I find the characterisation of all the characters and the interactions between each character much more interesting than those of any previous game. Old Ezio, while still feeling familiar, feels much warmer than he did in other games and many of his interactions with others are much more mundane than they have been in previous games, and for me that gives his character a much more endearing quality, this is expressed on your very first arrival at Constantinople, where you engage in a fairly standard conversation with a young man (who later on turns out to be very important) about the city itself. This extends to your first interaction with the Assassin leader in Constantinople, Yusuf Tazim, an immediately likeable character who you come to trust and care about later. This is something that I don't think can be understated, pretty much every character in the AC:R is a brand new creation and kudos to the teams at Ubisoft for making every one of them interesting to engage with. Also the reverence for Ezio's presence to the younger Assassin's was something that I enjoyed, the fact that he is the leader of the Assassin's yet it is being made clear that his time is nearing it's end, shown through the new tactics that the Assassin's in Constantinople use (the Hook Blade, bombs etc.), and more than once during the initial tutorials of these new systems Ezio, while still being called the master, is very much the student to a new generation of Assassins. The sense of community is at it's greatest for the first time since AC1, though this may be unsurprising as the crux of Brotherhood was to create the Assassin order.
Constantinople is very different from any other city in an Assassin's Creed game, the city feels much more alive than any game before it, with more interaction between citizens of the city and just the general atmosphere, a small but notable point are the dust clouds that descend on the city on occasion giving the environment a more dynamic feeling. It has been a nice departure from the architecture seen in the last 2 AC games, and the city seems to have been built with more care given to the free running mechanics, the addition of zip lines, parachutes (though I used them rarely) and in particular the Hook Blade meant the scaling and exploration of the city became quicker and more enjoyable in my opinion. However on my first play through I did find myself engaging in the buying of shops and restorations etc. I think because for the most part, AC:R felt to be a much easier game than even it's immediate predecessor, some say that this may not necessarily be a bad thing, but when it gets to the point where armour upgrades and weapon purchases simply do not happen due to the difficulty, the game has failed in ones of it's core mechanics, I failed even to buy the crossbow, which was one of my primary weapons in Brotherhood as I simply did not need it. Something else minor but still enjoyable for me was the music, the music in Brotherhood was very dark (it fit the tone of the game), but the music in Revelations reuses certain cues for AC2, giving the game a more hopeful feeling, and increasing the feeling of adventure.
As far as new mechanics go, AC:R has come under fire for not introducing mechanics that have had the largest impact, all sequels pay for the sins of their fathers, and the biggest sin I could level at the previous games (especially 2 and Brotherhood) is that they were really, really good, and the mechanics they added felt necessary and changed the way the game was played, especially with the recruitment of Assassins in Brotherhood. The new portions of Revelations that have been added don't nearly have the same impact. Firstly, I think everyone is in agreement that the tower defence sections are the games strongest point, they may not have been great but they never bothered me much, mainly because I only ever did them once in my entire play through, and the one I did I thought wasn't so offensive. The mechanic that I thought did not add as much as it could've was bomb crafting, for distractions or weapons etc. The problem with the bombs as they were presented was that they were meant to be used for scenarios that you had already come across in al the previous Assassin's Creed games, so at this point you already have a system in your own head of how to tackle the scenarios, so bombs add more of a distraction than a necessity.
My biggest problem with the game was far and away the Altair sequences. Problem being he had no presence at all, it may of been the fact that they had changed his voice actor (understandable, as all the voices in the original were such a random collection of nations), but the new voice actor had none of the presence or threat that the original had, and to be honest, Altair felt like less of a dick than he had been in the original, which seemed to be one of his defining qualities, his cockiness was gone and as a result as a player I felt less powerful. The overall arc of Altair's story as it plays out is interesting to watch as Ezio, but the character himself is frankly kind of annoying by the end of it, so the sequences which I came to the game to experience quickly became more of a chore to get through.
I should stress that these gripes that I have with the game did not detract too much fromt he overall experience, as they could either be completely ignored or were short sequences. On both my first and second playthroughs the overall feeling I took away was the sense of who Ezio was, and his struggle that had gone on for years. I have become more attached to Ezio more than pretty much any other game character over the three games he has been in, and will be sad to not play as him anymore, and I have to say that this was mostly down to Revelations characterisation of him as a wise old man on a last adventure, this was something that Brotherhood overlooked, Ezio in this game is less of an Avatar and more of a character, someone that you care about, and in Brotherhood I felt that was lost a little bit, and at the end of Revelations I was happy to have Ezio have a happy ending and that he made the decision to end his career as an Assassin, the game brings about a strange amount of closure for a one year iteration of series, Ezio's story is over, and I worry that I will not be able to attach as much to Connor in AC3 as I have to Ezio, but as I've said, this is the games greatest strength, and for me it's most commendable feature: it makes you care.