Review: Sifar for iPhone and iPad

Sifar by Takahiro Sakuda is a game in the tradition of Japanese logic puzzles.

Interestingly, it would have worked as a pen and paper puzzle, and the rules are simple enough that I wondered if it had been published before, but couldn't find any prior art.

You are given a grid containing some numbers. The goal is to mark some of the cells so that the total marked cells in the row and column of each cell (excluding the cell itself) is equal to the number written in the cell.

If you were solving the puzzle on paper, you would simply circle some cells and be done with that. The game makes things a bit cleaner: when you mark a cell, it subtracts 1 from all the other cells in the same row and column, so the goal becomes ending with a 0 in every cell.

In the example above, after selecting the top left cell the grid would change to this:

Then after selecting the top right cell:

After which, selecting the middle top cell would solve the puzzle.

The game contains at least 1000 puzzle at the moment, and they vary both in size (from 3x3 to 7x7) and type, for example some numbers may be missing:

Some cells may be missing:

Some cells may be larger (and therefore and be affected by multiple rows and columns):

If that's not enough, there's even a random puzzle generator.

The rules are easy to understand and there are some good logic deductions that can be made. It's possible to lock cells in their current state, which is an essential help in the harder puzzles.
I don't think it's guaranteed that all the puzzles can be solved without guessing. I surely wasn't able to.

The user interface is overcomplicated and feels awkward, but it's ok during the normal gameplay.

The game is free (with ad banners), the puzzles are good, so definitely give it a try.

 

Summary

Nontrivialness	★★★★☆
Logical Reasoning	★★★☆☆
User Interface	★★★☆☆
Presentation	★★☆☆☆
Loading Time	★★★☆☆
Saves Partial Progress	✘
Status Bar	✘

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