"Do you know what the definition of insanity is?," asks Vaas, the nutjob with the Mohican. "Insanity is doing the exact same ***king thing over and over again, expecting s**t to change. That is crazy."

As tempting as it is to read this as a veiled comment on the FPS genre, the fact remains that today we are doing the exact same thing - more or less. The behind-closed-doors presentation of Far Cry 3 covers the exact same ground that Ubisoft's press conference did, albeit with some minor changes here and there. So, when Vaas has finished his little monologue, he emphasises his final point by pushing a rock off a cliff. A rock which, if you remember, is tied to your feet. A split-second later you're thrashing about underwater, glugging and twisting, and trying not to look at all the drowned corpses that surround you. He's a nice bloke, that Vaas.

Here's a quick recap for of you who missed Ubi's show: Far Cry 3 puts you in the shoes of a chap called Jason Brody, who gets shipwrecked on an as-yet unnamed tropical island. Your girlfriend is missing, everyone else you know appears to be dead, and the island itself is populated with psychotic mentalists. At the start of the demo, you use your SLR camera's zoom to spy on what looks to be a nasty ethnic cleansing-type deal. Someone notices, creeps up on you, and knocks you out. When you wake up you're face-to-face with our friend Vaas, and we know how that turns out.

The nice thing about seeing the same level for a second time, and up close, is that it frees you up to notice little details you may have missed on the first viewing. For example, I hadn't noticed that numbers pop up in yellow font when you kill an enemy - something that seems to strongly suggest an XP system. At another point in the demo the player picks up an SD card. Clearly this relates to the camera in some way. We already know you can use it as a makeshift telescope, but the camera's presence on the game's title screen implies that it may have some other significant use. The obvious suggestion is that the SD card will be 'ammo' to let you take more pics, but to what end? If there is an XP or levelling-up system, could photography be tied into this?

While the presentation follows a similar path to the press conference footage, the demonstrator takes a different approach in the latter half of the demo. After wriggling free of his ropes and swimming to shore, knifing a hapless guard shortly thereafter, Brody approaches an expansive enemy camp. At the Ubi conference, Brody took a silent killer approach - at one point stabbing a guard with his own knife, and then flinging it into a second goon nearby. In this second playthrough, the player heads to higher ground, scaling a nearby hill. With the help of a handy sniper rifle, Brody thins out the guards via a smattering of lethal headshots. After this, he leaps onto a zipline and sails over a massive swathe of the camp, using a pistol to blast at foes with his spare hand.

After this, Jack's escape efforts follow the same path we saw before. He leaps into an enemy helicopter, grabs the pilot's pistol from his holster, and forces him to take off at gunpoint. This manoeuvre seems similar to the knife-swiping trick Brody performed earlier, suggesting that it may be a bread-and-butter mechanic. In any case, the hostiles outside shower the chopper with bullets as it takes off, but Brody returns fire. All seems to be going well until an unseen rocket (I presume) sends the helicopter spinning and then crashing to the ground.

There was no time for questions after the private showing, but I did get one of the developers to confirm that Far Cry 2's degrading weapon mechanic will not be returning. While the E3 sequence seemed a little more confined than typical Far Cry missions from the past, the demonstrators stressed that the game will retain the series' emphasis on open-world exploration. You may remember a mountain that was visible in the background at the very start of the demo, shortly before Brody was knocked out; apparently you'll be able to scale the thing - hopefully right to the peak.

Far Cry 3 isn't out till next year, but this initial reveal has certainly whetted my appetite. I was a massive fan of the last game - yes, even with all those respawning guards at the checkpoints - so I'm keen to learn more about what Ubi has in store for us this time. With any luck, we'll see a bit more at gamescom in August.

Far Cry 3 is due for release on Xbox 360, PS3 and PC in 2012.