That's right: Revelations genuinely does feature a tower defence mini-game. It's viewed from a pseudo-third-person perspective as you stand on a roof, sending archers and riflemen onto other buildings and barricading the streets to prevent invaders reaching your den. The viewpoint isn't particularly helpful, as it only gives you a view of a small section of the street, while unit assignment is unintuitive and fiddly. While after the first instance these sequences are essentially optional, you'll be forced into repeated bribes, den captures or assassin missions to avoid them. And until you've got a group of Master Assassins, if you want to expand your property empire around a certain area you're going to have to bite the bullet. Should the Templars take the den, you'll have to repeat the capture process, a process made more annoying by the cowardice of every den leader, as they'll sprint to safety as soon as you're spotted. Given that you need to use Eagle Vision to identify them - at which point you have no way of telling whether other guards have spotted you - this often leads to moments where you're surrounded by six enemies and your quarry has often escaped, forcing you to wait a day before attempting another capture.
Combat is much the same as it was before, although you'll find yourself running into tougher, more heavily-armoured enemies this time. Fortunately, bombs tip the balance back in your favour. Crafting them should be fun - you need to pick the shell, gunpowder type, and the effect they'll have - and you have a range of options at your disposal, from lamb's blood that showers enemies with the red stuff, causing them to briefly panic, to phosphorus light shows designed to distract. Pyrite coin explosions send pedestrians scrambling for fake money (handy when you're trying to create a diversion) and, of course, there are the more destructive kind including - joy of joys - sticky bombs. Trouble is, there's little reason to use anything other than impact bombs. Lob a fuse bomb and you'll need to wait three seconds for the explosion. Similarly, tripwire explosives are a nice idea in theory but take a good few seconds to set up, and it's all too easy to get caught laying them on the route of an enemy patrol.
The bombs also feel a little out of place. In a game where several missions require you to avoid detection - or reward you with full synchronicity for not being spotted - it's odd to be encouraged to lob bombs everywhere, even if a tactically placed smoke bomb can be a simple way to pass by a well-guarded door. Yet it can be something of a lottery whether they'll catch you through the fog. More than once I strolled off nonchalantly while guards were coughing and frantically wafting the air, only to see that telltale red triangle that showed I'd been discovered.
Brotherhood's tombs, meanwhile, have been replaced by linear platforming sections featuring lots of collapsing scenery and last-minute escapes where Ezio clings on for dear life. All we need is the occasional shout of "oh, merda" and we'd have a 16th century Uncharted. Still, as much as these moments owe a debt to Naughty Dog, they're undeniably exciting, presented with a cinematic flair that easily matches their inspiration.
Yet such sequences only serve to highlight the lack of inspiration in the game's other missions. The midsection of the game settles into a strange routine, as you run a series of basic errands (one has you tail a florist then pick tulips), before perching on top of a building and moving a cursor round to highlight glowing markers in order to uncover a secret location. The end justifies the means, but compare Revelations to the previous games' winning mix of scripted sequences and open-ended stealth-action and it comes up wanting. Even at its best, there's nothing here to match the atmospheric delight of Brotherhood's beautiful basilica in Palazzo Laterano.
Nowhere is this lack of inspiration more obvious than in Altair's missions. The five MacGuffins Ezio seeks during his Turkish adventure each corresponds to a playable section with the original game's hero. Yet the tasks are often tedious. In the first mission, you simply run up a hill and kill lots of guards. The second asks you to climb a building while bursts of energy from the Apple of Eden conspire to knock you down. The final memory involves little more than walking from one place to another.