You are provided four different games to choose from in Nikoli's Pencil Puzzle
: Sudoku, Shikaku, Akari, and Hashi. I'm sure that you have all heard of Sudoku. It's become a very popular game over the last few years. There are nine rows and nine columns, which also means there are nine boxes of nine (3x3). Every row, every column, and every box has to have 1 - 9 with no repeats on any. There is only one correct way that the puzzles can be solved.
Shikaku is a Nikoli original puzzle and is also known as Boxes. You have a grid with numbers on it. Each of those numbers tells you that that square is a part of a square or rectangle that has that many squares in it. It has to be a square or rectangle shape. L shapes or anything else that would have more than four corners is not a valid configuration. Once again, there is only one right solution and it can be deduced logically, which I like.
Akari is also known as Light Up. Once again, you have a grid with numbers on it. This time though, those numbers tell you how many lights will be placed next to that square. A light will shine down the row and column until it hits a solid box. No light can shine on another light, so you have to make sure that they don't overlap. The numbers show how many light bulbs have to be beside there, but there can be extra light bulbs not next to a number to fill in the gaps left, so start with the numbers and fill in as needed. Sometimes, you'll find that you have to move around the ones near the numbers to be able to fill in the gaps correctly.
Last but definitely not least is Hashi, otherwise known as Bridges. I think that it is my favorite of the puzzles. You have a grid with numbers on it, but this time the numbers tell how many bridges connect to that square. You must have that many, but not any more than that. When you have connected all that you need, it will grey out the square so that you know it is finished off. As with the rest, there is only one right answer, so you'll have to figure out tricks on how to get there.
All of the puzzles have the first five of each difficulty unlocked. This means that you will not have to play through the easier difficulty levels if all you want are the harder ones. You have to beat three of the first five to unlock the next five. You will have to beat three of the five that you just unlocked to get the next set open. Completing two of the previous set and one of the new ones is not enough. There should be enough puzzles total to keep you busy for hours and hours. I'm well over 10+ hours in and have barely unlocked some categories!