The devil is in the nerdy details, and the third Deus Ex game is starting to nail them down. We already knew it looked good. We already knew it appeared faithful to the talk/sneak/hack/shoot methodology of the unrivalled original. But there's an extra dysfunctional pleasure to knowing how many augmentations there are, how many ways you can upgrade them, how the inventory system works, how you get level-up points, what happens when you combine items, and what you can do when you hack security terminals.

You earn XP for killing, sneaking, hacking, talking, completing objectives – anything you could call progress. A certain amount of XP gets you one Praxis point – basically a level up. You spend Praxis on upgrades for your augmentations: each has its own mini skill tree of possible improvements. Praxis is meant to represent the way Adam Jensen gets more effective with his cybernetic implants as he uses them – the word itself is likely a corruption of the word 'practice'. Expect every review of the game to contain a box titled 'Praxis makes perfect'.

Right now, the game shows 21 augmentations divided into lots of interesting categories: neural, visual, defence, physical, movement, offence, and sound. Each augmentation then has a few different ways it can evolve: the Hacking Device, a neural augmentation, initially only allows you to open locked doors once you've hacked a security terminal. An early upgrade lets you also control cameras, and two later ones enable you to mess around with turrets and robots respectively. Along the way, there are four other upgrades that make the hacking minigame easier, effectively letting you tackle better-defended terminals. Now if you'll excuse me for a moment, I need to loosen my collar.

The augmentations that are confirmed or are obvious additions are: hacking, cloaking, speed, strength, mind-reading, a close-range explosive attack, X-ray vision, visual analysis, increased health, increased energy, increased lung capacity, soft landing, and comms (the classic guiding voice in your head). Ones that are very likely, from icons we've sneakily spied, are accuracy, temporary invulnerability, a map, a security alert delay, and silent movement. Be right back, I need a cold shower.

Even geekier good news is that Human Revolution has a proper, grid-based inventory system with proportionally sized objects – inventory Tetris. The second Deus Ex, Invisible War, simplified all this to a line of slots that could each hold anything from a flamethrower to a chocolate bar. Here, big guns take up lots of room, and they even change shape and size as you add mods to them. If that doesn't physically arouse you, you're a psychologically healthy human being and you have no business here.

You might have heard that the game has a regenerating health system – it does, but it's not like Call of Duty's. You have to avoid damage entirely for a lot longer before you start to heal, and you heal slowly. Slowly enough to need healthrestoring consumables if you're under heavy fire, and Human Revolution still has plenty of those.

It's getting hard to keep my excitement in check. It's the natural tendency of any fan – short for fanatic, lest we forget – to assume the worst, look for the flaws, and take any differences as detriment. That's a good thing – Eidos Montreal prowl forums and comment threads for every reaction to what they put out about the game, and they take it all to heart. But now it seems to have worked. Now there's less to assume, fewer flaws to find, and the differences seem increasingly positive. Do we dare raise our expectations from cautious optimism to open frothing? Personally, I'm not sure I have a choice.