Stackward: slide puzzle

Slide the shelves, open the aisle and deliver every volume in the order of the request. No clock, no enemy, no hurry.

You work the counter of an old archive. The shelves run on rails and only move along them; the order sets the sequence: volume I first, then II, then III. Your job is to open an aisle from the counter to the marked spine. It sounds simple until the third shelf, when clearing one blocks two behind it.

THE SPINE IS ONE SQUARE
Reaching the shelf is not enough: the volume sits on a specific row, facing a specific side. Coming at it from the end does not count. That rule is what turns shoving into planning.

AN EMPTIED SHELF STAYS ON ITS RAIL
This is the difference from the rest of the genre. Delivering a volume does not give the space back: the shelf stays exactly where it was, empty now, and still in the way. The archive never loosens up, and the last volume of the order fights the same crowding as the first.

DIFFICULTY THAT IS MEASURED, NOT MANUFACTURED
Each of the 250 levels was solved by a solver before it shipped, and the minimum number of moves is stored with it. That is why the game shows the optimum on screen while you play: the perfect score is genuinely reachable, not a guess.

UNDO IS UNLIMITED AND FREE
So is restarting. The difficulty in this genre is seeing the deadlock BEFORE you commit it, and nobody learns that without making the mistake and stepping back. The reachable aisle stays painted on the board at all times: the game does not hide from you what its own rule already decided.

FREE HINTS, AS MANY AS YOU WANT
When you get stuck, tap Hint: the shelf for the next move of the shortest path lights up, and a second tap shows which way it goes. No ads and no cost, and a hint never takes your score away.

250 LEVELS, ONE LIST
The first 60 are free. The next 190 come with The Stacks, in the SAME list: you carry on from where you stopped, and level 63 is level 63 before and after the purchase. One-time purchase, no subscription.

OUR SIDE OF THE DEAL
No clock, no lives, no score for speed. No ads of any kind: not to continue, not for a hint, not between levels. Playing is offline, with no login and no data collection at all. The game only talks to Google Play: to check and make purchases and, just once, to ask for a review.

Every volume carries its order number in Roman numerals as well as its colour, so the game is playable without telling colours apart.

Single player. Plays with no internet.

English, Portuguese, Spanish, German, French, Italian, Russian, Polish, Turkish, Indonesian, Japanese, Korean and Traditional Chinese.