I never played the original Shibuya. Nor have I ever been to Japan, let alone Shibuya district in Tokyo. So I had no idea that it was famed for its nightlife and spectacular advertising screens.

For the sake of the citizens of the real Shibuya, I hope it's nothing like its video game namesake. Otherwise everyone would be fleeing in screaming terror as massive blocks of pulsating pastel plummeted from the sky to a cheery chiptune groove.

This is an action puzzler. And like all the best action puzzle games it has a simple mechanic that's hard to explain and much, much harder to execute.

Geometric

Empty rectangles descend from the top of the screen at a speed dictacted by the difficulty setting. To the left is a little column showing a sequence of colours.

The first block you touch gets the colour at the bottom, then the column slides down to reveal a new colour at the top.

So you keep tapping rectangles as they fall, and each of them turns the colour at the bottom of the sequence.

Your job is just to make sure you get sequences of two or more colours together. Then you can tap the collection and the rectangles vanish.

Single ones stay on the stack, taking up essential screen real estate unless you can somehow free them and match them up with a partner.

Fail to keep pace with the plunging rectangles and let the screen fill and it's game over. Otherwise you're on a timer, and you're aiming for a high score before the clock ticks down.

Scoring is esoteric and confusing. Clearing the screen of colour gets you bonus points. Getting stacks of more than two gets you bonus points. Allowing a stack to accumulate and then tapping to shift several combos at once gets you bonus points.

Esoteric

There are optional tutorials that explain all that. In reality, you won't care. In reality you'll be desparately fumbling at the screen with sweaty fingers while swearing like a trooper.

In reality, you'll wonder how the human mind could ever hope to juggle geometry and colour fast enough to get any combos at all.

But if you want to progress in Shibuya Grandmaster, you'll have to learn.

The Grandmaster suffix to the original title hints at the biggest change in the game play. You're encouraged to try and earn ranks, from novice all the way up to Grandmaster.

Each has a checklist of achievements to tick off. Get ten four-block combos in one game. Get two thousand points on "fury" difficulty. That sort of thing.

It's a bit like the missions you get in endless runners. Except in Shibuya they're fixed in place. These goals make the game incredibly addictive. Not least because you'll have to work really hard to earn them.

Magic

After the first few ranks, you'll hit a difficulty spike if you want to progress further. Because the secret of Shibuya is that it demands skill at a whole bunch of different things at once.

There aren't tried an tested patterns to fall back on. Sometimes you make a combo by stacking colours together. Sometimes you make one by having lone matching colours sandwiching a different combo.

Sometimes you can chop and change to get colours to line up. Sometimes you desperately juggle individual stripes as best you can.

It's fast, furious and utterly enthralling. Ever so slowly you start to learn how to co-ordinate your fingers and your brain and that little stack of colours to do better.

The scores creep up. Another rank falls and it feels like victory. Bought at the cost of hours of practice and hours of tossing and turning at night, dreaming about neon blocks descending from the sky to crush you.

But it's worth it.