The hardest thing about Simogo's new game is that every movement must be made to the tick-tock beat of the music. Moving Bandit - a sprightly vigilante who's trying to reclaim a stash of stolen clocks - is as easy as tapping the screen, but it must be done to a steady beat.
So moving through Clockwork Mansion, dancing up steps and escaping through trap doors will sound like you're sending a Morse code message on your iPhone. If your tapping is out of tune, though, Bandit will simply refuse to budge.
The mansion's traps and hazards all move to the same beat with a predictable, clockwork choreography. Spotlights snap on, dopey guards turn away, trap doors swing open and steel doors snap shut.
Sneaking through each stage means learning the level's intricate patterns and exploiting those moments when Bandit can tip-toe through undetected.
It's often more about listening than watching for the perfect moment to strike. Each trap has its own distinct audio cue - spotlights squib, doors chirrup and guards go "derp" - which work together to build a unique soundtrack for every stage.
When you play the game right, stick to the beat and pull off a flawless run, Beat Sneak Bandit feels like you're playing as one instrument in a wider orchestra. There are plenty of times when the game swings closer to Guitar Hero than Metal Gear Solid.
But there's still a strong focus on stealth. When you're flanked by spotlights and a flying robot is creeping along to snatch you up, it offers a paralysing sense of fear that any Splinter Cell player will recognise. And it's that nervous tension that will lead you to tapping off beat.
Dud taps don't just leave Bandit standing still. Each level carries four bonus stopwatches: with one littering each storey of the screen. If you tap out of sync, the stopwatch on your storey will vanish into thin air.
As with many iOS pocket-money puzzlers, you don't have to grab these bonus clocks. You can simply clear the level by pilfering the main clock without being detected.
But working out how to nab those optional timepieces will show you Simogo's smart puzzle design, and seriously challenge your rhythm skills. The secret levels you unlock are a nice prize, too, but the sheer satisfaction of mastering a level is often reward enough.
Beat Sneak Bandit is a devilishly clever idea - and one that has been executed almost flawlessly. It's that sort of game that makes you ask "why has no one made a rhythm-based stealth game before?"
It is disarmingly addictive, and by far the most original game to hit the App Store in ages. Even if you're a bit rubbish at it, it's impossible not to fall in love with this funky little number.