There is an abundance of what we'll call "line 'em up" games - where the goal is to line up at least trio of same-coloured shapes to blast them away and make room for the next set - but none more engaging and, at times, infuriating than King.com's Candy Crush Saga. It's got cutesy graphics, it's saturated with sickly-sweet colours, it's somewhere between Tetris and Bejeweled and it's so testing that it'll keep you busy for many an hour.Candy Crush Saga\nFormat\niOS, Android\nPrice\n\u00a3Free (69p for each additional level set later in the game)\nWhere\niTunes | Google Play\nIt's also rather difficult. The opening levels aren't too taxing and get you used to the game's dynamics while dashing through the almost Mario-level map, laden with unicorns, dragons and other cardboard-cut-out-styled characters.First on the agenda, you've got lives. No less than five of the blighters, so on the approach to being rather cat-like except that, in a more alien-esque way, lives regenerate slowly over time. So while this means you have five attempts at any one level, give it about an hour or so and you'll be back to full lives again and can recommence that level that seems impossible to beat.Second is the way Candy Crush works: the placement of various coloured "candies" - or sweets as us Brits like to call them - is apparently random at the start of each level. Sometimes you'll get dealt a good board, sometimes you won't. The goal is to match trios of the same colour for them to pop into a shower of sugary points, allowing the seemingly endless supply to continue to trickle down from above.But it gets more complex than that. Match four to generate a sugary bomb that will detonate a full line either horizontally or vertically, while five will create a sweet with apparent sherbert fizz: it'll zap all of one selected colour off the board.Making T-shapes and L-shapes will generate an explosive candy bomb that destroys a three by three grid twice over. Better still combine these specials for various massive effects - an essential to beat some levels.The problem is, because of the random board arrangement, it can be a right ole pain to get any good combos or lines together. A little forward thinking can help, but it's easy to get backed into a corner where no moves are left available and then the board will auto-refresh.Levels are arranged in to a variety of types, some easier than others. There are point-scoring ones, jelly-popping ones and others where you'll be pulling your hair out at the "chocolate monster" that devours everything in its path. The difficulty is definitely up there - we've spent days on level 70 and still can't beat it.Just to be extra tough each level has its own specific number of moves available. Some can be completed with loads of moves spare, which instigates the "Sugar Crush" finale, while later down the line you'll be wondering why there aren't an extra dozen moves available. Patience and, it would seem, lots of luck all play a considerable part in Candy Crush Saga.Unless you're loaded with money that is. Here's the sour part, like face-screwingly sour: in a bid to fill up their coffers with real money the game's developers have added a shop to buy five extra moves, hammer lollipops and other special items that are 69p a go. For just one. Didn't Mother always tell you that you could have just a handful and no more? If you're not the patient type that could get really, really expensive.Worse still, after completing several of the lovely, child-like worlds the game starts to prompt for either an amount of Facebook likes or a further 69p purchase for the next world. A bit of a shame really, as this game's good enough to pay out, say, \u00a31.99 up front and enjoy it all the way through - but the developers have other ideas.Sweets do seem to inspire greed, don't they? But so sweetly addictive Candy Crush Saga is that we've struggled to keep our distance and that's what makes it one of our choice apps.