This makes it sound more impressive than it actually is. It's conceptually interesting, but the puzzles are poorly designed and often frustrating. It desperately wants to be Portal, but it has none of the ingenuity.
The main motivation for completing these journeys is revealing Desmond's past. He's always been fairly one-dimensional, but this gives him some presence as a character. It's just a shame Nolan North plays him so closely to Nathan Drake. The similarity is distracting.
But back to Ezio. Of the many new skills he picks up in Constantinople, bomb making is the most entertaining. Using ingredients looted from chests or bought from stores, you can craft three different types of bomb: lethal, tactical and diversion. The type of casing you use affects the bomb's behaviour. You can make them bounce off walls, stick to surfaces or explode instantly on impact.
Caltrop bombs cover the ground in sharp spikes that can slow enemies down; useful if you're being chased. Throw a blood bomb at an enemy and they'll panic, thinking they've been fatally wounded. Datura bombs release a cloud of poison gas, and tripwire bombs can be used to set traps.
Those are just a few examples. There are potentially hundreds of combinations. It's an enjoyable toolkit, and in a way reminds us of Arkham City's gadgets. You can perch quietly in the rafters, mixing different bomb types to confuse enemies, temporarily blind them, or separate a lone soldier from a group for a silent assassination.
Most stealth sections can be completed by simply alerting the guards and stabbing them all to death with your sword, but if you want to play more strategically, the bomb system offers a wealth of tactical options.
Oh, and it's funny too. There were a few laughs in Assassin's Creed II, but they were relegated mainly to cut-scenes. In Revelations, some missions are designed purely to make you laugh. One of the best sees Ezio dressing up as a wandering minstrel, complete with a feather in his cap and leg-hugging white tights. As you prance around a party in the Sultan's palace distracting the guests with your off-key singing, your fellow assassins slip into the group and quietly kill key targets.
It does remain a rare moment of imagination and humour in an otherwise overtly serious game. But when you're making Ezio sing and twang his lute, or firing poison darts at guards from a distance to make the locals think they've fallen under a gypsy curse, you can't help but admire the game's humour and creativity.
Other attempts to add variety aren't quite as successful. Two on-rails horse-and-cart battles are clumsy and irritating; something that would have been far more entertaining as a cut-scene than a twitchy, barely-interactive mini-game.
Occasionally, as you move through crowded areas, a Templar assassin will stab you in the back, severely reducing your health and forcing you to give chase - even if you're in the middle of a mission. In fact, many of the missions are unremarkable and meandering, making the story about five hours longer than it needs to be.
However, the hunt for the Masyaf keys brings out the best in the developers. Each one presents a different challenge - be it sneaking through a cavernous cave network undetected, or chasing Templars through crumbling ruins as they hurl bombs at you.
These self-contained moments are some of the game's best, and each one offers a new type of gameplay. They're often heavily scripted, reminiscent of Uncharted, and somewhat brief, but you'll always look forward to the next one blinking on your mini-map. Then when you finally reach the key itself, things get even more interesting.
It's no secret that the third playable character in Revelations is Alta´r, Ezio and Desmond's distant ancestor, and hero of the original Assassin's Creed. Each Masyaf key contains a memory from his life that Ezio can interpret, and that you get to experience first-hand. There are five in total, and they pick up immediately after the events of the first game, spanning multiple decades until Alta´r is an old man.