The best iOS games for anyone addicted to gem-swapping - Simple, compelling videogame concepts can provide familiarity along with a foundation for innovation. This means you can pick up and play a game that's largely based on a concept you know and immediately figure out how to play, even if the changes result in a radically different experience.
One such concept is tile-matching, popularised by PopCap's Bejeweled series. Although other tilematching/swapping games preceded it, Bejeweled's online distribution, polish and game design ensured it cemented itself as a leader in its field.
It therefore follows that if you're on the hunt for a match-three game for iOS, you should first go back to the source. With Bejeweled 2 + Blitz (59p, iPhone) , you get four modes, including the traditional Classic and Attack (swap gems, wait for the grid to refill and continue until there are no more matches or, in Attack, you run out of time), Endless (a casual, stress-free mode lacking a timer and ending) and the frenetic, exciting Blitz. The last of those ties in with the Facebook Flash game, and you have one minute to get as many points as possible.
Unlike Bejeweled's other modes, Blitz doesn't force you to wait until gems have settled before you make another swap - instead, you rapidly switch gems and create chains as more jewels fall into the well. Given Bejeweled's relative simplicity and the fact that PopCap's game is so polished, there's little point in considering the myriad clones that litter the App Store.
Instead, go further afield, exploring games that expand the basic concept. Piyo Blocks 2 (£1.79, iPhone) appears similar to Bejeweled but has enough innovation to warrant purchase.
Gameplay is based solely around Blitz-style mechanics. Piyo mode has you match a quota of each tile type to advance, while Hyaku levels up when you acquire 100 of any tile. You also get Time Attack, Endless, Three Seconds (make a match within three seconds or your game is over) and Disco (regular board refreshes) modes.
Piyo and Hyaku's timers are too lenient, making those modes easy for match-three aficionados, but the game's fun nonetheless. Avoid the HD version for iPad though - instead of blowing up the seven-by-seven grid, it adds more slots, unbalancing the gameplay.
Rather than including extra modes, many match games offer depth through quests. Paradise Quest(£1.79, iPad) tasks you with matching tiles that represent resources that can be used to restore the Galapagos Islands. As you make a match, the board lazily scrolls in that direction, enabling you to explore the large levels and uncover objects required to progress.
For a pseudo-educational game, the tiny wildlife photos collected and static viewable environments are disappointing, but the gameplay's interesting, despite a lack of help regarding how to use objects. (Hint: tap on the map and tap where you want to go when using the vine.)
Around the World in 80 Days: The Game (59p, iPhone) is similar, if a mite simpler, with you completing the famous voyage by moving objects to the bottom of the grid for collection. Plenty of variation in board layouts, special tiles and the game's polish and responsiveness make it a great purchase for match-three fans.
Some quest-oriented games ramp up the role play side of things. Puzzle Quest Chapter 1 and 2(£2.99, iPhone) and Puzzle Quest 2 (£2.99) task you with completing numerous quests in a fantasy world of goblins, spells and demons.
The match-three mechanics are used for one-on-one battles; skulls represent attacks and coloured gems are Mana, which can be used to power spells that inflict further damage on your opponent. Both games have their fans, but we feel they're a bit grind-orientated rather than outright fun, and the sequel is hugely weighty and badly optimised, although it does offer plenty of depth and game time.
If we're honest, we'd sooner settle down with Dungeon Raid (£1.79, iPhone), which distills Puzzle Quest down to its essence. Instead of swapping gems, you match by drawing lines through objects: shields to power up your defences; money to buy new kit; potions for health; and weapons and skulls to attack the latter.
Strategy comes from positioning pieces so you can attack skulls, and the role-play mechanics add a touch of extra depth to keep you coming back. As a bonus, there's no tedious traipsing around maps.
Alternate match mechanics are the other major way in which games inspired by Bejeweled have made their mark. Azkend (£1.79 for iPhone or £2.99 for Azkend HD for iPad) uses Dungeon Raid-like line-drawing, but in a rather more sedate, thoughtful setting.
Devil Invasion (59p, iPhone) boasts a hexagonal grid and uses somewhat similar combat ideas to Dungeon Raid but as a means of fending off, castle-defence-style, a string of monsters attacking you at the top of the screen.
Crystal Soul (59p, iPhone) has each match move a character around the grid, forcing you to use limited moves wisely.
Chop Sushi! (59p for iPhone or £2.39 for Chop Sushi! HD for iPad) makes the single change of having you move pieces to the edge of a board to shift all the others inwards (a simple difference that rapidly made our brain hurt - but the game's fun cartoon graphics kept us hooked).
Some games deftly emphasise the gravity aspect within match games. Toy Balls! HD (£1.19, iPad) has balls bouncing around the place, which you must save from getting zapped by stringing together matches, Dungeon Raid-style.
Linkoidz (£1.79) has you grab an alien from the pile atop your shield and fling it back to make a match. Take too long and the shield fails, resulting in your spaceman becoming a snack for the ravenous aliens.
The extremely pretty, superficially relaxed Liqua Pop (59p, iPhone) brings you more down to earth, dragging together coloured bubbles of liquid that encourage a frog to climb a stem when they burst.
Finally, the amusing Greedy Bankers (£1.19, iPhone) emphasises gravity within match games by doing away with a well-orientated play area entirely - instead, the grid is viewed from above, and you drag like-coloured gems together to create larger, far more valuable ones, with the aim of making enough cash before the timer runs out.
It's amazing to see how the basic concept of match-three games has been expanded and tinkered with to create so many familiar yet varying games - and the indie-friendly nature of the App Store ensures many more will arrive over the coming months, which is sure to make even the most ardent match-three fan happy.
As for the games covered here, they're all worth considering, but because we've mentioned more than usual this issue, our shopping list only features the cream of the crop.
