The concept behind Picross is fairly simple. You are given a blank grid - from 5 x 5 to 25 x 20 - and it is up to you to find out which square is filled in, and which isn't. Every square has a logical solution, and using the hints found at the top or left of every column or row respectively you will slowly paint yourself a picture with nothing but logic and your stylus.

The game is broken up into three main game modes and a few other multiplayer and single player modes to help increase your speed. The Easy Mode is exactly that, the puzzles are easier, the grids are smaller, there are only 15 puzzles and most of you won't spend much of your time in here, and if you do, you'll be finished with it soon enough and moving onto the real stuff: Normal Mode. This mode is identical to Easy Mode in every way except that the further you progress the bigger the grids get. You start this mode with the ability to enter only a few of the different levels. Every level is themed and broken down into 15 puzzles and three bonus games. The game is entirely non-linear, so if you don't feel like finishing off the fruit themed levels, jump on over to the slightly harder zoo animal puzzles inside Level 2.

The 15 puzzles found in every level are organised into 3 rows of 5. Finish the top 5 and you unlock the Catch mini-game. The second row unlocks the Sketch mini-game and the last row unlocks Hit. While these mini-games are fairly easy in Level 1, you'll be struggling to get them finished by the time Level 4 or 5 comes around. Catch sees you trying to tap moving squares, Sketch has you trying to copy the image seen on the top screen, and Hit asks you to tap on squares before they disappear. While nothing major happens upon completing the mini-games, the more puzzles you get finished within an hour - sounds like a long time, but, with the penalties dished out, you'll need it - the more Levels you unlock, of which Easy mode has 10.

The puzzles aren't all fun and games, however, and guessing which square is filled is not something that is recommended. Every wrong hit results in a time penalty, two minutes for your first wrong guess, four for your second and eight minutes for every wrong hit after that. It's about using logic to uncover the picture and being precise is completely necessary.

This is where the only games bug makes itself known. For the most part the game runs smoothly, and you'll very rarely have a bad thing to say about the title, but sometimes you'll tap a square only to find a time penalty added because the game thought you hit the one next to it. No amount of recalibrating will sort this issue out and it seems to get worse the further down the screen. As long as you make sure you hit the middle of each square you should be fine.

So what happens once you finish with Normal Mode? If you manage to keep yourself sane and wishing for more puzzles after the 150 Easy Mode has on offer, then you're in luck as Free Mode waits for you. Free Mode is the evil version of Picross. You have no time limit, but you also have no idea if you're right or wrong with your placement of filled in squares. The only way you know you've got it right is that you get told so at the very end of the puzzle. Finish the puzzle but get it wrong and it's up to you to find out where you went wrong. While it's not impossible to do, thanks to the number clues greying out once you have a row or column completed correctly, it can be frustrating. Expect another 150 levels in this mode with at least 30 minutes of play-time per level in this mode.

The great thing about Picross DS that sets itself apart from other puzzle titles is the way it teaches you the game and then continues to help you improve. When you first power it on you'll be given some step-by-step instructions on what filling out a Picross is all about, and following in Brain Training's footsteps, there is a Daily Picross mode. Once a day you can see how fast you can do five basic puzzles.

Feel free to fill in the crosses to help you figure out what goes where, and over the months you play this game try and beat your time. After three days the second Daily Picross mode unlocks. This time you have five puzzles to do and this time you're not allowed to place crosses down, and the puzzles are a little harder. Four days after that you unlock another mode, and so on. It's a great way to help you improve and to keep the title interesting.

But that's not all. Once you've finished all of the Normal and Free Mode puzzles and can't get anymore out of the Daily Picross mode you can always start creating and sharing puzzles with friends. An extremely simple level creator shows you the ins and outs of making puzzles to send wirelessly to your friends, and with Nintendo's Wi-Fi Connection you'll be sharing with your mates while they're not even around.

But that isn't the only thing you'll be using the WFC for. Not only can you upload your puzzles for your friends, but you can download packs of puzzles released earlier in Mario's Picross on the Game Boy and SNES in Japan. But, again, that's not all. A challenge mode sees you against random competitors in a race to complete 2 puzzles in a row. While most of the gamers you will come across will have stats in the thousands, don't let it put you off. They will be faster and better than you at first, but once you've wracked up thousands of games, you'll be just as good.