The amazing reception and excitement to its E3 debut cools rapidly due to dicky right stick sensitivity come our hands-on with the London mission; a degree of lag that makes precision shots tough going.
And precision shots are all-important in this zombie survival horror. Sparse ammunition, the rareness of firearms and overwhelming odds means a missed headshot can be the difference between life and death in Zombi U's apocalypse. Awkward aiming an issue that challenges anyone playing to stay alive for more than five minutes.
For all its appeal, Zombi U's nearby clipboard - pads attached to every Wii U demo unit here today as helpers ask questions and scribble notes after every play - seems packed with 'constructive criticism' comments. Likely its the same feedback replicated to page's end.
That's the immediate issue. But we know it'll not be a lasting one. This is a game still early on in development, and everything else about the title shows too much promise to decry the entire endeavour on an early build's dodgy aim.
On looks, Zombi U shambles past Valve's two Left 4 Dead releases, the series closest in form to Ubisoft Montpellier's efforts and likely the franchise the game will be most referenced to. Our runs though an office block show the immense clutter of small details - office desks with personal effects, a children's creche littered with disused toys - yet also a sterility to the environment that recalls Valve's duo for attempted realism. It'll pack detail to best effect: a glimpse at a storm-lashed Buckingham Palace with burning wrecks and palace guard zombies proves Zombi U, and Wii U, are no slouch in the set piece department.
The background cleanliness is there so the game's brain-dead antagonists are easier defined by your torch's light and your weapon's aim or swing. Few in number, and a mixture of classic shufflers and lunging modern types, these undead are incredibly deadly, mainly due to a the game's life expectancy equation: one bite = death.
You've got a one-off life-saving syringe to beat back a grabber, but retreat and thinning down the herd is definitely the best option - melee weapons such as a cricket bat allow you to block, push back and swing, but you will be overwhelmed if you don't approach the problem with scientific precision rather than over-emotional zeal. Shaun wouldn't last five minutes here.
Die - and you will - and you'll be respawned back at temporary base camp as a new survivor. The game's tagline "how long will you survive" is less tasty marketing spin, more central gameplay premise. Come death a timer will flash on screen as to how long you lasted. Continual looks at demo pod screens during the afternoon of Nintendo's Wii U hands-on rarely sees anything past five minutes. Hell knows what the endgame is supposed to be, or if there even is one. We can't see eventual extraction being on the cards; the game's tangent towards eventual brain-death too depressing to offer even that glimmer of hope.
But from that comes a cool idea: your character will remain in the world, brimming backpack and all. To earn those collected goodies back you've got to track their carrier down in your new guise, kill them, and pickpocket the corpse.
It's at this point we see one of the crucial mechanics of the game in effect. Interactions with anything within the game world - coded locks, or as here, riffling through your backpack - will occur on the Wii U Game Pad screen without the game pausing as you do so. You've seen the moment at Nintendo's press conference video were you're frantically trying to decode an Underground access door panel on the tablet, while tossing frantic glances at the main screen at the nearing flesh-hungry masses.
It's an amazingly potent idea; even watching we felt anxious. First time it happened to us, as we spent too long studying what useful items we could transfer between our downed ex-survivor's backpack and our own on the tablet only to be jumped, we flinched in surprise.
Mini-games such as these have broken up the pace, even given some breathing room for players in other titles. Done right and Zombi U may need to come with a heart attack warning on the box - we only hope the variety of tablet uses matches the ferocity of concept.
Yes, it needs polish. Yes, we need to see, and play, a lot more to grasp how and if the terror's going to be sustained through longer game sessions. But it's Zombi U, along with Rayman Legends, that are proving the best reasons for Nintendo adding tablet functionality to their new machine: smart concepts that add extra unique flavour to our current gaming experiences. It'll be these, not party games, work out regimes, or use as a standalone gaming device, that'll state Wii U as a must-have experience.