Spellsquares [$1.99 / HD], an atmospheric word puzzle game from Benthic Games, hit the App Store with its iPad version back in June. We missed out on it then, but we picked the game up on its iPhone release this month. It's right at home on the small screen, maintaining an enchanting mix of exploration and challenging puzzles.

In Spellsquares' story mode, you find yourself wandering a castle with a mystery to solve. A mysterious stranger has left notes to guide you on your way (kind of him, since you're out to foil his nefarious plan). Each door, treasure and point of interest is blocked with a word puzzle that you'll need to solve. The puzzles are crafted like Sudoku for words. A square grid is laid out with a few letters already in place. A pool of available letters sits to the side. Your job is to use those letters to make words in every row and column at once � easy puzzles require three-letter words and the hardest require five. Solving them takes a little bit of logic and a touch of vocabulary. Once you factor in hints, you'll also need a dash of strategy.

As you explore the castle, you'll discover hidden coins in every room. Those can be taken back to the Oracle, a ghostly automaton that entreats you to pick a card, any card. In exchange for your coin, you'll receive one of three hint items to help you on your way: two that reveal correct letters in single squares, and one that will confirm every correct letter you've placed in a particular puzzle. The hints are plentiful, but they aren't unlimited. Conserve them, but don't go overboard. There's no benefit to making it through the game without turning to hints aside from personal pride.

I found the game challenging enough that I was pumping coins into the Oracle fairly often, but your mileage may vary. If you find the game too easy and you didn't choose the hardest mode, restart and push it up a notch. Rushing through on Easy and then replaying on Medium or Hard will be a disappointment. The puzzles are the same; they just give away fewer revealed letters, so you'll be redoing puzzles you've already solved.

Spellsquares' story barely deserves to be described as such, but I don't count that against the game. It's a familiar tale: evil wizard does something evil, and an anonymous hero comes to uncover the mystery and defeat the plot. It serves to add a sense of exploration and purpose to the puzzling, and does an admirable job of that. Exploring the castle wasn't a thrill, but it was a nice break to clear my head between puzzles.

The story comes to a conclusion after you explore 14 rooms and solve a few dozen puzzles. But the game isn't over at that point. Completing the game unlocks Quick Play mode, with 60 puzzles of varying difficulty. You're given no hints for these ones, so they'll add a dose of challenge if you're still hooked.

An excellent user interface rounds out the Spellsquares experience. It isn't flawless � I found trouble placing letter tiles in lower squares at times, for instance � but it has one feature that every similar game should learn from. You can walk away from a puzzle at any time, and when you return your tiles will still be where you left them. If you need to head back to the Oracle mid-puzzle or you decide to move to a different room and return later, your progress remains intact. Saved me a headache or two, that's certain.

With over 100 puzzles to work through, Spellsquares offers the word-puzzle fan a lengthy and entertaining experience. It won't last forever, but its well-crafted puzzles are a joy to work through once. If you missed out when the iPad version was released, now's your chance. While you're at it, pop into our discussion thread to share your impressions.

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