Fire Balls 3D is the latest game to benefit from that Voodoo magic. It's stormed to the top of the iTunes charts in both the UK and the US.

If you're someone who hasn't played the game before, it's kind of a super-casual twist on the shooter. Kind of.

There's a stack of coloured hoops, which look a bit like a lighthouse. You press the screen to fire a stream of cannon balls into that lighthouse, knocking it down one layer at a time.

In the way are a bunch of randomly rotating blocks, on hit of which spells game over.

It's fun, in its own simplistic way. But it won't last forever. So what do you play next?