Concursion is a twisted, thrilling and unique mash-up of genres

Concursion, quite frankly, is an ugly game. On the surface - in stills, and in motion, too - it is, anyway, its unwieldy artwork clunking along in an unpleasant, garish blur of clashing colours and unsightly characters. Yet Concursion, when played at a decent lick by someone who has mastered its strange, unique systems, is breathtakingly beautiful - a clash of genres that are bought together by deft finger-work and some remarkable invention from developer Puuba.

The idea behind Concursion is pure in concept, but surprisingly - brilliantly, even - elastic and playful in execution. It's a mash-up of well-established, well-worn video game genres, where platformers cascade into shooters and then segue into hack and slash before neatly depositing you in a Pac-Man-esque maze where you're gobbling up little dots, and it manages to mix everything together effortlessly. Well, after a little effort from yourself, anyway.

Concursion's genres manifest as bubbles within the flatly drawn levels, each one whisking you away to a different set of conventions, controls and enemies. It's a strange, slightly warped feeling you get as such disparate worlds collide together, though developer Puuba - and, more specifically, the chap who's behind Concursion, the fast-talking, wide-eyed and infectiously enthusiastic Danny Garfield, embarking on his first game project - has been wise to gently introduce the novel mechanic. What starts off as a simple side-scroller mutates through the course of some 70 levels into something as twisted as it is thrilling.

There's a stern challenge at the heart of Concursion, as steep as anything offered by the likes of Super Meat Boy even if offers a more bizarre incline, and taking apart a few seconds of high-level play reveals how tightly woven Puuba's concoction can be. Abilities unique to each genre bleed into one another: enter into the hack and slash genre and you'll have a double jump, while pass through the shooter one and you'll have a neat ranged cannon, and it's possible to use the mechanics of one of the games to conquer an obstacle in another.

At its simplest it's a little dizzying, but a little further down the line it climaxes into a mad mess - double jumps are chained together through drifting bubbles of hack and slash where you somehow float through entire levels, breaching new genres and new worlds like a dolphin briefly escaping the inertia of the ocean. Later still, genres gain some sort of sentience and chase you across entire levels - and I can't think of anywhere else where you can feel the chill of being hunted down by a slightly banal looking ninja game. It all feels like the kind of game that should be inherently broken, but Puuba's masterstroke is in making it all hang together, somehow.

So Concursion is kind of ugly, but bubbling away underneath the sometimes grotesque artwork is a work of real imagination, and, even more impressively, a feat of considerable engineering. It's on Steam Greenlight right now, with a view towards a full release on PC and Mac later this year.