Version tested: iPad
Some great shooters are original, but the vast majority are variations on a theme. Mix up the same elements, give or take, and add an ingenious twist: et voila! Such is Super Crossfire HD, one of those games that's always reminding you of others, and a shooter precision-engineered around one clever idea.
The key trick here is instantaneously warping between the floor and the roof of the 2D level, a mechanic that isn't just a joy to use but is hardwired into enemy movement and how the waves work. It has basic puzzle elements - enemies will fire at the surface you're on, but it takes them a second to turn, or they have one side that's invulnerable, or they're protected by a shield - that depend on smart warping, but the trick is in being able to do simple calculations fast under fire.
Because you are constantly under fire, the black-bordered neon visuals (with an especially cool 'burnout' effect) give deadly life to pulsing energy bolts of all shapes and hues. Staying in one place for too long results in bullet hell raining down on your position, which can either be woven through or immediately warped out of. But such is the pace of Super Crossfire's shooting that most deaths come from warping out of one deadly situation and, under pressure, warping straight back in before the bombardment has passed.
This iOS release also forms part of an increasingly familiar pattern, where so-so XBLA games are given a new lease of life by the touch-screen. But whereas with Burnout Crash it was all about the controls, Super Crossfire has been reworked - here it's a much faster game, with even partial waves a threat rather than a formality. After the first world things can get relentless, and it's here the touch controls prove they can handle frantic action, while the pumping techno keeps you blasting.
Despite this pace the waves are firmly separated from each other, meaning you have to kill every enemy before the next one appears, so Super Crossfire's levels feel a little like a series of high-speed challenges interspersed with quick breathers. Generous continue points are spaced out in the midst of levels, as are opportunities to upgrade the ship's abilities, so that the first playthrough becomes a trial-and-error of learning the various tactics before one big run ties everything together.
This isn't really a high-score kind of shooter. Doing well nets you victory points that can be used for unlocks in the main menu (including one that doubles the points you get), but Super Crossfire's more about the journey - seeing what strange combination comes up next, learning how to take down a seemingly impervious wave, and making snap decisions at warp speed. Original and familiar, breathless and smart, Super Crossfire hits contradictory notes. But when it works, which is often, this is something beautiful.
App of the Day highlights interesting games we're playing on the Android, iPad, iPhone and Windows Phone 7 mobile platforms, including post-release updates. If you want to see a particular app featured, drop us a line or suggest it in the comments.