Android phones and tablets have increased in popularity, the number of apps available for the platform has rocketed.
And that means more free Android games. There's a lot of junk out there but, fortunately, there are gems among the junk.
We've worked our way through a whole load of Android games to reveal the ones you should download to your phone.
If we've missed your favourite free Android game, let us know in the comments.
We also have a video run down of the top 10:
1. Angry Birds
The amazingly popular iOS game moved to Android a while ago, earning over two million downloads during its first weekend of availability.
The Android version is free, unlike the Apple release, with maker Rovio opting to stick a few adverts on it rather than charge an upfront fee. The result is a massive and very challenging physics puzzler that's incredibly polished and professional. For free. It defies all the laws of modern retail.
Bebbled is your standard gem-shuffling thing, only presented in a professional style you wouldn't be surprised to see running on something featuring a Nintendo badge with an asking price of £19.99.
You only drop gems on other gems to nuke larger groups of the same colour, but with ever-tightening demands for score combos and scenes that require you to rotate your phone to flip the play field on its head, Bebbled soon morphs into an incredibly complex challenge.
3. Red Stone
There's an awful lot of square-shuffling games on Android and Red Stone is one of the best. And one of the hardest. You start off with a big fat 'King' square that's four times of the normal 'pawn' squares, then set about shuffling things so the fat King can get through to an exit at the top of the screen.
It's hard to accurately describe a puzzle game in the written word, but seriously, it's a good game.
Released a few months back in beta form, Newton is a maths/physics challenge that has you lining up shots at a target - but having to contend with the laws of nature, in the form of pushers, pullers, benders (no laughing), mirrors and traps, all deflecting your shot from its target.
The developer is still adding levels to it at the moment, so one day Newton might be finished and might cost money. But for now it's free and a great indie creation.
5. Sketch Online
Surprisingly free of crude representations of the male genitalia, Sketch Online is a sociable guessing game where users do little drawings then battle to correctly guess what's being drawn first. It's like Mavis Beacon for the Bebo generation. The version labelled "Beta" is free, and if you like it there's the option to pay for an ad-free copy. But Google can't make you. Yet.
Some might call Drop a game, others might classify it as a tech demo that illustrates the accuracy of the Android platform's accelerometer, thanks to how playing it simply involves tilting your phone while making a little bouncy ball falls between gaps in the platforms. Either way it'll amuse you for a while and inform you of the accuracy of your accelerometer - a win-win situation.
7. Frozen Bubble
Another key theme of the independent Android gaming scene is (ports of) clones of popular titles. Like Frozen Bubble, which is based around the ancient and many-times-copied concept of firing gems up a screen to make little groups of similarly coloured clusters. That's what you do. You've probably done it a million times before, so if it's your thing get this downloaded.
8. Replica Island
Replica Island is an extremely polished platform game that pulls off the shock result of being very playable on an Android trackball. The heavy momentum of the character means you're only switching direction with the ball or d-pad, letting you whizz about the levels with ease. Then there's jumping, bottom-bouncing, collecting and all the other usual platform formalities.
9. Gem Miner
In Gem Miner you are a sort of mole character that likes to dig things out of the ground. But that's not important. The game itself has you micro-managing the raw materials you find, upgrading your digging powers and buying bigger and better tools and maps. Looks great, plays well on Android's limited button array. Go on, suck the very life out of the planet.
Another coloured-square-based puzzle game, only ConnecToo has you joining them up. Link red to red, then blue to blue - then see if you've left a pathway through to link yellow to yellow. You probably haven't, so delete it all and try again.
A brilliantly simple concept. ConnecToo used to be a paid-for game, but was recently switched to an ad-supported model - meaning it now costs you £0.00.
Once you're successfully rewired your brain's 25 years of playing Tetris in a certain way with certain buttons and got used to tapping the screen to rotate your blocks, it's... Tetris.
It hinges on how much you enjoy placing things with your phone's trackball or pad. If you're good at it, it's a superb Tetris clone. Let's hope it doesn't get sued out of existence.
UPDATE: While Titres seems to have been removed from Google Play, there's now an official Tetris app available to download.
Not the best-looking game you'll ever play, with its shabby brown backgrounds and rudimentary text making it look like something you'd find running on a PC in the year 1985. But Trap! is good.
You draw lines to box in moving spheres, gaining points for cordoning off chunks of the screen. That sounds rubbish, so please invest two minutes of your time having a go on it so you don't think we're talking nonsense.
Coloured gems again, and this time your job is to switch pairs to make larger groups which then disappear. That might also sound quite familiar. The good thing about Jewels is its size and presentation, managing to look professional while packing in more levels than should really be given away for free.
We had to put one Sudoku game in here, so we'll go with OpenSudoku - which lives up to its open tag thanks to letting users install packs of new puzzles generated by Sudoku makers. It's entirely possible you could use this to play new Sudoku puzzles for the rest of your life, if that's not too terrifying a thought.
Abduction! is a sweet little platform jumping game, presented in a similarly quirky and hand-drawn style as the super-fashionable Doodle Jump. You can't argue with cute cows and penguins with parachutes, or a game that's easy to play with one hand thanks to its super accessible accelerometer controls.
16. The Great Land Grab
A cross between a map tool and Foursquare, The Great Land Grab sorts your local area into small rectangular packets of land - which you take ownership of by travelling through them in real-time and buying them up.
Then someone else nicks them off you the next day, a bit like real-world Risk. A great idea, as long as you don't mind nuking your battery by leaving your phone sitting there on the train with its GPS radio on.
17. Brain Genius Deluxe
Our basic legal training tells us it's better to use the word "homage" than to label something a "rip-off", so we'll recommend this as a simple "homage" to the famed Nintendo Brain Training franchise.
Clearly Brain Genius Deluxe is not going to be as slick, but there's enough content in here to keep you "brain training" (yes, it even uses that phrase) until your battery dies. The presentation's painfully slow, but then again that might be the game teaching you patience.
Coloroid is aery, very simple and has the look of the aftermath of an explosion in a Tetris factory, but it works. All you do is expand coloured areas, trying to fill them in with colours in as few moves as possible - like using Photoshop's fill tool at a competitive level.
Cestos is sort of a futuristic recreation of curling, where players chuck marbles at each other to try and smash everyone else's balls/gems down the drain and out of the zone. The best part is this all happens online against real humans, so as long as there's a few other bored people out there at the same time you'll have a real, devious, cheating, quitting person to play against. Great.
20. Air Control
One of the other common themes on the Android gaming scene is clones of games based around pretending to be an air traffic controller, where you guide planes to landing strips with a swish of your finger. There are loads of them, all pretty much the same thing - we've chosen Air Control as it's an ad-supported release, so is technically free.
GalaxIR is a futuristic strategy game with an abstract look, where players micro-manage an attacking alien fleet. Pick a planet, pick an attack point, then hope your troops have the balls to carry it off. There's not much structure to the game as yet, but that's what you get when you're on the bleeding-edge of free, independent Android gaming development.
Graviturn is an accelerometer based maze game, where the aim is to roll a red ball out of a maze by tilting your phone around. Seems embarrassingly easy at first, until increasing numbers of green balls appear on screen. If any green balls roll off the screen you die and have to try again. It's abstract. It's good.
23. Alchemy Classic
There are a few variants on Alchemy out there, each offering a similarly weird experience. In Alchemy Classic you match up elements to create their (vaguely) scientific offspring, so dumping water onto earth makes a swamp, and so on. It's a brain teaser thing and best played by those who enjoy spending many hours in the company of the process of elimination.
In ActionPotato you control three pots. Pressing on the pots makes them jump up into the air, where they harvest potatoes. See how many you can get in a row. That's the gist of it. And don't collect the rotten potatoes, else you die. That really is it. The Google Play stats say this is on well over 1,000,000 downloads, so it's doing something right.
25. Scrambled Net
Scrambled Net is based around the age-old concept of lining up pipes and tubes, but has been jazzed up with images of computer terminals, high score tracking and animations. Still looks like something you'd have played on a Nokia during the last decade, but it's free - and looking rubbish hardly stopped Snake from taking off, did it?
Dropwords is laid out like your standard Android block-based puzzle game, the difference here is we're not dealing with gems - you make blocks disappear by spelling out words from the jumbled heap of letters. There's not an enormous amount of point to it, but you can at least submit your scores and best words to the server, where an AI version of Susie Dent will pass her approval.
What you do in Barrr is man-manage a bar world, pointing men at the beers, games or tattoo parlour, then taking their money off them once they're drunk and happy like a good capitalist. And make sure they go to the toilet. Things, as things do in games, soon start speeding up and it gets rather insane and difficult.
The name gives it away - this is a Tetris clone. Or rather it's a game that uses the same sort of block-shifting rules as Tetris, only with a very nice and user friendly touchscreen area beneath the block pit to make it easy to play. We're having trouble locating this on Google Play at time of writing - either a glitch or the inevitable legal troubles.
UPDATE: Tetronimo seems to have been removed from Google Play, but there's now an official Tetris app available to download.
Wordfeud is a superb little clone of Scrabble, with a big, clear screen and online play options that actually work. The game's been offered for free with some hefty advertising over it thanks to the developer being based in Norway - which only received paid-for app sales support recently. A paid version may arrive soon, but Wordfeud remains free right now.
30. Friction Mobile
Friction Mobile is a very odd concept that makes no sense in still images. You fire a ball into the screen, then try to hit that ball with other balls until it explodes. The catch is you're not allowed to bounce balls backwards into your own face. Because then you die. Sounds rubbish, but works well. It's free, so give it a no-obligation, no-commitment whirl.
Geared is a weird little thing finally converted over to Android from iPhone. It's an embarrassingly simple concept - players slot different sized cogs into place on the screen, with the aim being to power one gear from another. Then, as is video game tradition, it gets harder and harder. Plus there are 150 levels of it all.
A stunning little retro game, Meganoid plays and looks like something that ought to be running on a Nintendo emulator. But it isn't. It's new and on Android. It's a speed-based challenge, using on-screen or accelerometer controls to jump and bounce through ever-hardening levels. Developer Orange Pixel is aggressively supporting it, too, with constant map packs, characters and more regularly appearing for download.
A standard and traditional platform game. Cordy is a speed-based affair, with players running, jumping and collecting their way through its pretty green levels, using an electrical cable to jump, swing over obstacles and grab energy. Uses on-screen buttons so can be a bit tough to play, but comes with 12 free levels to get you going.
34. Angry Birds Rio
Yet more Angry Birds for fans of the simplistic trial and error physics game. Angry Birds Rio is another chapter-based effort as well, with developer Rovio leaving tempting empty slots on the menu screen for periodic updates of new levels. More of the same, but with a prettier, 3D look to it this time thanks to a vague association with animated movie Rio.
35. Grave Defense Holidays
As with Angry Birds, the maker of this superb tower defence game has spun out a separate version it fills with seasonal levels. Recently updated with an Easter map, this free version of the game also includes Valentine, Christmas and St Patrick's Day themed maps. Currently calls itself Grave Defense Easter. Easily one of the best examples of the tactical genre.
36. Words with Friends Free
The popular iPhone Scrabble-alike is now on Android, with an ad-supported version up on Google Play for free. Words with Friends Free should actually be called Words for People Without Any Friends, as once installed it lets users play with complete strangers online - or pick specific people from your contacts list. It's turn-based, so several ongoing games can be strung out for days.
Very similar in style and concept to Xbox and Xbox 360 retro classic Geometry Wars. In fact, one might legally be able to get away with calling it a right old rip-off. Android PewPew is a rock-hard 2D shooting game packed with alternate game modes. It's a bit rough around the edges and requires a powerful phone to run smoothly, but when it does it's a fantastic thing.
38. Tap Fish
A nice looking little aquarium, that combines the timeless hobby of staring at goldfish with game elements based around breeding new varieties. There's a slight sting in the tail here in that Tap Fish is one of the initial wave of "freemium" Android games brought into life thanks to Google's launch of in-app billing. The really cool new stuff costs little bits of money.
39. Beats, Advanced Rhythm Game
A standard rhythm action, button pressing music game for Android. Beats manages to outdo the official music games by including a Download Song tab, where it's possible to install new song files created by users. It's very hard and very fast. Just like they should be. Runs perfectly on an HTC Desire, too, so there's no blaming glitches for not doing very well.
40. Pinball Deluxe
Pinball Deluxe is an actually decent pinball sim for Android, and it's free. At the moment it comes with four tables - Wild West, Carnival, Space Frontier and Diving for Treasure. Ball movement is convincing, and although a bit of the magic is lost thanks to having to use on-screen buttons, it's a smooth enough experience. It's ad-supported. Don't press those. You don't get a bonus.
41. Winter Walk
Winter Walk is madness. You play the part of a gentleman, out for an evening walk. From time to time the wind picks up, so you have to hold on to his hat to stop it blowing away.
While this is happening, the chap's internal monologue appears on screen, giving you an entertaining and distracting read in the process, too. Very simple, but a perfect little high score challenge game for the touchscreen era.
42. Colosseum Heroes
Publisher Gamevil takes a break from churning out the role-playing games to give dumb action a go here. Colosseum Heroes is a 2D slasher, where you simply try to survive for as long as possible, building up your armour and weaponry to make yourself tougher and meaner.
Technically this is a "freemium" game paid for with in-app purchases, but if you're prepared to spend a while building up your character's skills manually, there's no need to pay out.
43. Stardash Free
Developer Orange Pixel has a knack of creating excellent retro titles, with Stardash a fine example.
Designed to look like a Game Boy game from before many of you younger readers were born, Stardash is clearly a bit of a Mario homage - but it's done exceptionally well and is endlessly replayable. If you like it, and you probably will, there's an alternate paid version that removes the adverts.
44. Scramble With Friends Free
Zynga's latest puzzler Scramble With Friends Free is technically a free game, but in order to get the most out of it and play as it's meant to be played you'll need to use the in-app purchasing system to buy "tokens" to let you access games quicker. Which leaves a slightly bad T-A-S-T-E in the M-O-U-T-H, but at least it's free and perfectly playable at a slow pace if you're just curious.
45. Dead on Arrival
Dead on Arrival is a very impressive looking 3D survival horror game, which dumps you in a hospital infested with zombies. You then try to not get eaten by buying new weapons, boarding up doors to keep the brain-eaters at bay and using wall-mounted weaponry to quicken the zombie mincing process. As with many of today's Android titles, there's the option to pay for stuff within the game to unlock features and remove ads - but you don't have to.
46. Stick Cricket
Stick Cricket is a fantastically simple little game that reduces cricket to its core values - you just smash every ball as hard as you can. There's no worrying about field positioning, just a bat and a ball coming at you very quickly. Initially it seems impossible to do anything other than make a complete mess of things and having your little man smashed upside-down, but it soon clicks.
47. Draw Something Free
Draw Something Free is the new phenomenon that's taking the world by storm (at the time of writing, at least). It's basically a mobile version of Pictionary, where you're given a choice of three words of varying difficulty, then tasked with drawing them so someone can tell what it is. Syncs with Facebook, too, for easy cross-platform play. If you like the free trial, there's a paid accompaniment with more content.
The popular web-based Flash game Fragger is now on Android. It's pretty much a clone of Angry Birds, mind, offering simple physics-based challenges based around chucking grenades all over the place to make stuff blow up. It comes with some rather intrusive ads, but that's the price you (don't) pay for sticking with the free version.
49. The Sims FreePlay
Global mega-corporation EA has gone literally mad, giving away its Android version of The Sims for nothing in the form of The Sims FreePlay. In return for sitting through some full-screen adverts every now and again, players get a decent mobile version of The Sims, complete with pets, plants, lifestyle points and all the usual mundane activities that make the series popular. It's not perfect, but does fit in most Sims core features.
50. Super Bit Dash
About as far away from The Sims as you can get. Super Bit Dash is a retro-style 2D platform game, with controls as simple as its pixel art design. The game runs at a constant pace, so all the player has to do is jump and super-special-jump at the right time in order to avoid smashing into the scenery. Obviously it's a lot harder than that makes it sound.