[This is part two of PSM3's huge MGS4 cover feature. Part one can be found here. Pick up issue 100 of PSM3 for the full feature, including extra info and loads of awesome new screenshots].
The good stuff
Some random observations: while the demo section's similar, there's now a battlefield tannoy at key moments, where a robotic female voice chirps propaganda to the PMCs (accompanied by a nursery rhyme jingle), reinforcing the corporate nature of war. You can wake up unconscious guards by standing over them and tapping w (the context-sensitive 'action' button) - far better than shaking them like in MGS2. It's incredibly easy to trip alerts.
We must've started 20 in the Middle East section alone, and since there are so many guards, you can't silence alerts like an 'Off' switch using CQC as you could in MGS3 - offending our inner Obsessive Compulsive/Autistic. Sound plays a major role, with a fine line between silent tip-toeing, and noisy treading - you need to be really delicate with the analogue stick. Impressively, it's much easier to sneak around in active battlefields, since the noise of war drowns out your footsteps.
More insight: the 'Stress' and 'Psyche' meters play a more important role than you'd think. In prolonged combat, or boss encounters, Snake's Stress level rockets (like a reverse countdown, with ours often hovering around the 80% mark), increasing his resistance and aiming accuracy.
The flip side, is that extreme stress causes Snake's Psyche to crash, which means his stamina heals much less quickly. It's really important to hoard Arsenal Compress or Recovery items (like a Ration) to restore Psyche - smoking and reading girlie mags has the same effect, but work less quickly.
There's a great in-joke where Snake's psyche drops a quarter of a bar during cut-scenes whenever anyone mentions how old he looks, or when Sunny threatens to take his cigarettes away.
Back to the game - once you've met the MkII robot (from the trailers), you descend into the Militia base, where the TGS playable demo ends. Snake finds a Militia outfit to replace his Octo-Camo, allowing him to blend in.
Be warned - we accidentally killed an ally, and spent the rest of our time fighting through the tunnels. Switching allegiance between warring factions is as simple as who you last killed. In one set-piece, fighting alongside the militia, a friendly soldier accidentally blundered into our sights - leaving you battling both sides as your allies turn against you. Highly annoying.
Make your way through the underground base - note the wailing injured militia and the still-wobbling wing of the Raging Raven robot birds on a tabletop - and you meet up with guns dealer Drebin, who outlines the game's Weapon upgrade/purchase system in a whopping cut-scene. See 'How Drebin Points Work' - but it's not dissimilar to the excellent weapon customisation system of Resident Evil 4.
Guns range from Mk22 tranquilisers, to M16s, to P90s to full-blown automatic grenade launchers - plus the usual RPGs, Javelins and C4 charges. Every weapon feels unique, and can be customised with stocks, sights and grenade launchers, creating your own personal attachments.
Fight the power
When Drebin's finished, you navigate a section we won't spoil, before bumping into Akiba - who's enjoying a toilet visit in a barrel, as seen in the last trailer. He sprints off, and you engage in an epic street battle, engaging snipers - either head-on using cover, or by finding a sneaky alternate route - before taking on a distant enemy tank, fighting alongside the militia.