Nurikabe Vault is, in short, a must-have iPhone application for those that like logic puzzles.  The concept, according to Wikipedia, was invented by the same guys that came up with Soduko.  It’s more graphical and less numerical though.  If you like PathPix, you are going to feel right at home with this $2.99 title.  Like PathPix, your game level starts out with some numbers.  Your goal is to connect “blocks” or “boxes” that total up to the number.  These connected boxes can only connect vertically and horizontally.  But there is an interesting twist that sets these 500 levels apart from games like PathPix.  Your collections of squares have to be divided by a “path” that is no more than a single square wide.  And it too has to connect in a single unbroken line that doesn’t break or try to go diagonal.  Two different collections of squares can touch diagonally, but that doesn’t “count” as a connection.

The game interface is incredible.  A lot of thought went into it, and it shows.  What you can’t see in the screen shot to the left is that those background graphics that look like green gears actually rotate or move slowly.  The initial menu also uses this gears-type theme.  In it, you have an inner wheel and an outer wheel that you rotate to get to the level number that you wish to play.  A status message at the bottom of the screen tells you if the level has been completed or in progress.  If you have completed it, it tells you the best time you have for reaching the solution.

Once you get into a game level,  touching a gray square and dragging your finger will add adjoining gray squares.  You can do the same if you are adding to the “path”.  Tapping any square (except for the ones with the numbers on them) will rotate though the options of a “block”, a “path”, or neither.  Once you finish a level, the button on the bottom of the screen to undo a “move” changes to to one that takes you to the next unsolved level.  The levels also auto-complete once there is only one choice left and that choice solves the level.  I wish this was an optional thing though as sometimes, as I neared completion, it completed it for me before I had that “Aha!” moment and realized that I had solved it.  It almost made me feel cheated because I had not fully figured out that I had figured it out.

Like I said, the game comes with 500 different levels, each with a unique solution.  The levels are divided over five different “worlds”.   Puzzle sizes range from the simple 6×6 grids like what I’ve displayed here, but go up to 9×11…basically three times the size of the small ones.  In order to get from one “world” to another, you need to swipe horizontally on the main menu screen.  This is not as obvious as it could be, but takes you to the larger levels with the different graphical themes associated with that “world”.

The game graphics are incredible, but the minimalistic “clicking” sound effects are perfect for listening to your own music or, like me, an audiobook while you play.  One future enhancement that I would love to see would be the ability to start the titles or playlist from within the game so that you can also stop it when things get hairy and you need to concentrate, but don’t want to just mute the sound and loose your place in the book.

Nurikabe Vault also includes OpenFeint support for leader boards.  You can also challenge your friends.  Other game features are not quite as obvious though.  If, for example, you split up your “path” so that it isn’t continuous, it will “tremble” or “shake” a bit to get your attention.  Same goes with a collection of the “boxes” or “blocks”.  If you don’t have enough in the collection, it will “twitch” a bit.

While the game costs $2.99, I think it is well worth it.  A free version with 20 levels is available if you would like to try it out.  You can also become a fan of their Facebook page where occasional promo codes or news is announced.  I’d highly recommend the Wiki page as well.  Not only does it do a great job of laying out the rules and some strategy tips, but when you look at the graphics there, it really shows you how far Nurikabe Vault goes in setting itself apart with an an incredible implementation of a classic logic game.