Tucked away at E3, shielded from the glare of the main presentation for reasons unknown, was Project P-100. It's an all-new superhero action IP by well-lauded developer Platinum Games, due to be published by Nintendo in Wii U's launch window. It's also bonkers.

One Mr Hideki Kamiya is at the helm as director, famous for a track record that includes Viewtiful Joe, Devil May Cry, Okami and Bayonetta — plus for his apparent desire to make a new Star Fox game at gunpoint. It's the first game in that impeccable list that P-100 takes the most from, with a bit of Pikmin sprinkled in for seasoning. The world is being attacked by gigantic mechanoids, and with a haphazard array of have-a-go heroes it's up to you to defend it.

P-100's style is appealing, but not particularly extravagant. It's presented in isometric viewpoint, with people that share the body characteristics of Viewtiful Joe, pin-legged and stern-faced — except when they're reduced to wide-eyed, arm-flailing panic. It seems to be inspired by action figures more than anything else, an over-the-top fantasy toy box where anything can happen.

The mass-action hero game starts you off with a few troops; ordinary citizens who've come together out of desperation, wearing anything to hand as makeshift superhero costumes. Sadly for one guy the closest thing was apparently a toilet, but he wears the porcelain with pride. Your group can be expanded whenever you meet fleeing citizens – draw a circle around them on the touch screen and they'll join your merry brigade of misfits.

People power's what it's all about: the more help you have, the better use you can make of Unite attacks, which let you pull your followers into formations to solve puzzles and, primarily, smash up dozens of robots. Once you draw a shape on the touch screen – or flick the right analogue stick in the corresponding direction – and press a button to confirm the selection, your weird bunch can work together to form oversized weapons and tools.

Drag out a vertical line from bottom to top and they'll stand on top of each other to act as a humongous sword to swipe at enemies; sketch the vague shape of a gun, a half square pointing right, and a green pistol the size of a building is yours to wield. The circle is used to ball everybody up into a big red fist, which can be used to punch enemies or turn switches to open new paths.

With all this at your disposal you'd think there'd be no problems fighting off an invasion, but you're restricted by a battery meter that drains whenever these powerful moves are used, which ties in with the toy world feeling. Instead you've got to mix in more normal attacks, commanding your team to punch and kick enemies with their own little bodies, to keep the energy charged up. There's also emphasis on well-timed dodging and swift blocks — by morphing into a jelly for a few seconds, naturally — to keep the pace flowing. The combat overall is quite simple, but pleasingly so. It's probably a good job, with tons going on very quickly.

In the demo we trotted around town battling against the numerous threats, from smaller robots to tanks that were ten times our size, before eventually facing up against a boss whose arm filled the entire screen. The aim was to dodge its lasers and punch at glowing nodes until we could eventually build a bridge of people over to other parts of its body to continue the assault.

The level shown in the demo was pretty linear, with few ways to step off the main path; we hope it's slightly more open in the end. There was an optional opportunity to duck inside a building at once point, however, by using the hand to open a garage door. Once inside the action switched down to the GamePad screen, flipping the viewpoint from isometric into over-the-shoulder third person, while the television screen remained focused on the outside world. The aim was to change a number on the outside of the building; you had to adjust some interior valves on the GamePad screen while keeping an eye on the television to make sure that it was working. It's a rather inventive use of the GamePad – we'd like to see more of this.

There's always a lot going on in P-100; pure chaos, in fact, to the point where it's actually quite difficult to take everything in. It's undoubtedly fun, with satisfying combat mechanics and a massive infusion of invention, but it was only midway through the ten minutes or so demo that things started to click and a better sense of when to use each formation developed. We wish we'd been able to play more to gain a more coherent viewpoint, though judging by the insanity at play narrative coherency might be the last thing to be found here. If Platinum Games is let loose, P-100 could be a real ace up Nintendo's sleeve during Wii U's early months.