This series is getting messy. The original Splinter Cell may have been nowhere near as fun as this, but it felt tighter. To guide greying US ultra-espionage agent Sam Fisher to success you had him jumping around to the full extent of his athletic ability, seeing the world through the three vision modes on his ubiquitous goggles and always utilising something from his extensive arsenal of gadgets.
But with each sequel more moves have been introduced, more gadgets, more super-lucky security holes to make use of. You know the kind. Man-sized vents, built big to allow those really big bits of air through; lengthy pieces of seemingly decorative rope that someone could hypothetically climb but honestly, who would want to do that? With the release of Double Agent the wealth of options available to you in any situation increases again, but this devalues things slightly.
Knocking out a guard becomes a matter of which process you think you'd enjoy more. Zap him with your sticky shocker? Fire a nonlethal airfoil round? Spray gas from a sticky camera? If you like the gas idea you could try a gas grenade instead, or a wallmounted gas mine. Or you could give that handy nearby valve a spin and release some inexplicable knockout gas. Not that you need any of this. As the Best of the Best you can cheerily dispatch the Rest with a tap of the right mouse button, rendering foes catatonic with a smack to the chops even if they've spotted you.
Whether you're any good or not, Double Agent will make you feel like the baddest of asses, but it's a superficial feeling. It lacks the sense of achievement you'd get from a stronger stealth game. Fortunately, Splinter Cell isn't trying to be one of those pofaced, challenging stealth-'emups. Not any more. And this is why Double Agent is the best of the series so far. Ubisoft understand that what the series does best is dramatic moments, little sequences or actions that make you go "Oooh", or giggle, or draw you in, and this game is rammed with them. This is where the Double Agent part comes in; more on the 'moments' later.
Easing you in gently, the first mission gives you six minutes to disable a warehouse-sized missile while avoiding guards, then shimmy up your extraction helicopter's dangling rope before it explodes. In the helicopter Sam gets the news his daughter's been killed in a car accident, but because Sam looks perpetually miserable anyway we are informed of his pain and rage by him throwing his trademark goggles out of the window. A new and excitingly broken man, he takes on an undercover mission that involves him spending the next six months in prison to infiltrate the terrorist group John Brown's Army. He is no longer Sam Fisher, man in latex. He is Sam Fisher, man in orange boiler suit, sans Agency support.
A nice side effect of being all alone is a sense of being plugged into the plot for the first time in a Splinter Cell game. There's no longer a voice in your ear going "Jesus Sam! There's been a plot development! You have to infiltrate this building!" Most intel comes from your own drawer-rummaging, computer hacking and eavesdropping, and you don't need some overweight crouton back home to tell you what it means. This, along with the game's strong atmosphere, creates a real emotional link.
This is where things get interesting. The rest of the game has you carrying out work for the bad guys while spying on them and occasionally subverting your own objectives. Between missions you get to kick back at terrorist HQ where you're given some menial task to do and 25 minutes in which to do it. The tasks can be finished early or you can slack off completely (with repercussions) and spend the rest of the time limit doing other jobs around the base or completing work for your secret masters (planting bugs, getting fingerprints, etc), desperately attempting to boost their respective trust meters.