English Country Tune [$4.99] is a game that’s hard to describe. It’s a puzzle game, one loosely based off the original block-pushing mechanics of the long-standing Sokoban. Its puzzles arrange themselves in complicated 3D designs, except that sometimes they’re two-dimensional. The goal is to free certain blocks from a prison of others, or maybe it’s to put all the balls in their holes, or perhaps it’s to paint every free tile in a level. That changes. Sometimes it’s hard, other times it’s easy, and not necessarily in a linear order.

Here’s what I can say with some certainty. Increpare’s English Country Tune has made the transition from desktop to mobile boldly and without compromise. It’s a game that will stump even the most experienced puzzle gamer at times, and it’s absolutely inflexible about easing you past those difficult points. It’s not a game for the easily stymied, but it will do an outstanding job of challenging puzzle experts.

It begins simply enough. You control a flat panel that can flip itself over and over on the surfaces of blocks. You control the panel with swipes in all directions. You must push a ball, the Larva, into a particular space. Not so bad, right?

Then you learn that the Larva is effected by gravity, and that gravity is determined by the position from which you push it. Knock it down from above and you might send it flying down, but hit it from the side and it may move along that plane with you. Then the Larva levels twist themselves into knots, leaving you to follow along with your understanding of the mechanic as things go completely off the rails.

Completing one section will branch off a new path. This one teaches you about Whales. Whales need to be free, and can be pushed off the level. But you can only push them by running into beams of light that shine from each of their sides, so you often have to find a way to run parallel. Then the Whales also find themselves brought into three dimensions and things get kind of weird from there.

And so it goes. Each time you may think you have a handle on a mechanic, you’re introduced to a new one. You’ll paint blocks, then learn you have to do so in 3D. You’ll find yourself punching holes in your panel to squeeze past obstacles. Occasionally things will get extremely strange, pushing the boundaries of every bit of game design you’ve seen so far.

Throughout this process, you’re lead level by level through a series of branching paths that sometimes come to a sudden end and sometimes pull back in on themselves. This may leave you with punishingly challenging choke points and no way past but through. There is no level skip, no walkthroughs, no assistance. But on the brighter side, there are no timers, no move limits, no one watching you and tracking your performance. You can play and experiment, try everything you can think of to find your way through. It’s refreshing to be so unconstrained.

Less refreshing is English Country Tune’s camera. It is essentially uncontrollable, following along behind you as you go. You can use two fingers to pan around, but it snaps back into position immediately. This occasionally leaves you with no way to see your panel, or whatever you’re trying to interact with.

This is the unfortunate kind of frustration, the kind that can’t be alleviated with perseverance and eventually success — you can’t succeed over an occasionally uncooperative camera. It’s bad enough that I was left in a particularly challenging level staring at the bottom of the construction while I moved around on top. When the camera finally moved, it did so dizzyingly. While this sort of thing occurred rarely, it was crippling on those occasions.

On a related note, another quibble: in a game where levels can be long and extremely complex, positioning the reset button immediately adjacent to the undo button is cruel.

Otherwise, English Country Tune is rare treat: a puzzle game filled with variety, but trusting in its players enough to get out of their way. The visuals and music are subtly stylistic — the game looks and sounds fantastic, but not so striking as to distract. The interface is uncluttered. Nothing judges your performance, but no one will help you either. This is puzzling at its purest, and it’s sure to challenge anyone willing to step up.