It isn't enough to cobble features together and call it a game - there has to be something more to it.
For a game like Robot Unicorn Attack Heavy Metal Edition pieced together from a formula that generated an earlier hit, there's a critical component missing.
Robot Unicorn Attack wasn't a success because its gameplay was amazing: it was a blast because it was hilarious. The over-the-top music, the cheesy graphics - satire transformed a formulaic running game into a piece of interactive pop art.
Robot Unicorn Attack Heavy Metal Edition, on the other hand, feels like just another endless running game.
How it worksIn control of a robotic unicorn, your goal is to run as far as you can by leaping over gaps and dashing through metal stars in a single never-ending level. You're given three tries to run as far as possible, at the end of which your three runs are totalled and your overall scored posted online.
The pair of double-jump and dash abilities do set Robot Unicorn Attack Heavy Metal Edition apart from other running games, although both are inherited from the game's superior predecessor.
All the elements of a good high score running game are here, yet the heavy metal theme disappoints. While the heavy metal scene is ripe for parody, the game doesn't take it far enough.
How it doesn't workThe music isn't hardcore enough to be funny: it sounds more like a slightly angry Bon Jovi cover band than grating heavy metal. Strident numetal or the unintelligble screaming of a German metal group would give the game the edge it desperately needs. There's no way around it: the track falls flat.
At least the game has the right look. The severed unicorn head that greets you at each game's end is sufficiently graphic and the bones cobbled together for each floating platform are suitably morbid. Curiously, high resolution graphics aren't supported.
Solid gameplay is boosted by integration with OpenFeint for leaderboards and achievements, though much of the fun is cut into by the poor choice of music. Robot Unicorn Attack Heavy Metal Edition is one of those rare cases where style is more important than substance and it unfortunately doesn't hit the right note.