The growing user base of Google's Android mobile operating system has attracted some truly talented game developers. Great games are available from the Android Market, but it's not always easy to find the best. This guide will familiarize you with some of our favorites.

We embedded a QR code next to each review so that you can easily install the games. In order to interpret the QR codes, you will need to first install a code reader application such as Zxing's Barcode Scanner. If you are reading this article on an Android device, you can simply tap the barcode image and you will be taken to the relevant entry in the Android Market.

Bonsai Blast

Bonsai Blast is an arcade-style ball-blaster created by Glu Games. Columns of colored marbles roll through tracks that snake across the playing field. The player must prevent the marbles from rolling into holes that are positioned at the end of the tracks. In order to do this, the player uses a cannon to fire matching marbles at the marble columns. When a marble is fired at one of the columns, it will snap into the row. If it lands next to two or more marbles of the same color, all of the consecutive matching marbles will vanish. The cannon is operated by tapping the desired target on the touchscreen.

The game has a campaign mode with 90 levels and a survival mode in which the player selects a level and plays it for as long as possible while the speed of the incoming marbles steadily increases. In survival mode, the game will track the user's best time and score for each level.

Each level of the game is styled like a Zen garden. Although the same basic style is used across all levels, the season and time of day differs from one level to the next so that there's some aesthetic variation in addition to changes in the level layout. Excellent artwork and addictive gameplay set Bonsai Blast apart from many other games on the Android platform. The game is free in the Android Market, though it displays advertisements between levels (but not during actual gameplay).

Robo Defense

Robo Defense is a challenging tower defense game by Lupis Labs. Players lay out defensive towers and weapon turrets in order to prevent enemy units from crossing the battlefield. The towers can also be upgraded with resources that are accumulated by destroying enemy units. Because the enemies use both land and air units, players must strategically organize their defensive towers in a manner that will protect against both kinds of entry.

The game has five separate maps and 10 difficulty levels. Some of the more advanced maps have multiple entry and exit points, which can make the game considerably more challenging. A pause and fast-forward feature makes it possible to take your time or accelerate the enemy assault.

The artwork in Robo Defense is well-executed, but it's not visually stunning—the units and terrain look good, but the user interface is simplistic. The game can also be time-consuming; fortunately, it will automatically preserve its state between uses so you don't have to play through a full level in one sitting.

Robo Defense is available from the Android Market. The free version only includes the first map, while the full five-map version costs $2.99. After testing several tower defense games for Android, I believe that this one delivers the best user experience.

Jewellust

Jewellust is an Egyptian-themed Bejeweled clone by Smartpix Games. The game presents the player with a field of gems in various colors and sizes. The player swaps the position of adjoining gems in order to create matching sets of three or more. After a match, the matched gems disappear and new ones will fall into the field.

While matching gems, players also have to obtain pieces of a hexagonal mosaic displayed at the bottom of the screen. The pieces are mixed into the playing field alongside the jewels. In order to collect a mosaic piece, the player has to match enough gems to get it to the bottom row. If the player gets all of the pieces of the mosaic within the time limit, he can advance to the next level.

Much like Bonsai Blast, Jewellust has a campaign mode and a survival mode. The campaign mode has 30 levels and an assortment of simple mini-games, such as one where you have to find the right order in which to press a set of panels.

The game looks reasonably good, but its user interface remains a bit clumsy, almost as though it had been ported from a feature phone; this just doesn't feel like a native Android game. That doesn't detract much from the quality of the gameplay, however.

Jewellust is available from the Android Market. The limited trial version is free and the full version costs $2.95. The developer, Smartpix Games, has also released a sequel called Devilry Huntress which has 40 levels and a Halloween theme.

The Inferno

The Inferno is an action game created by TBS Games that's (very) loosely inspired by Dante's Divine Comedy. The player guides Dante through hell, where he must collect lost souls (floating blue orbs) while avoiding traps like spike pits, lava pools, ghosts, and fire windmills (what, you don't remember the fire windmills in Dante?). After the player collects all souls on each level, the exit gate will activate, allowing the player to proceed to the next level.

When the player accidentally walks Dante into a trap or a monster, the character will die and then restart from the last checkpoint. The checkpoints appear frequently in each level, which means that there is little penalty for dying, though the game does track the player's total number of deaths with a counter in the top left corner. You can control Dante by using the on-screen directional arrows or your phone's trackball or D-Pad.

The Inferno is plenty enjoyable to play, but I was disappointed to find that there isn't much of a puzzle aspect in finding your way around the levels. The game's challenges primarily involve properly timing your character's movements so that you don't hit any of the traps. The controls are a bit weak, which can be frustrating sometimes, but this handicap is evened out by the lack of serious penalties for dying.

The game's artwork is elegant and impressive. The various circles of hell have their own distinctive style and appearance, so you get a decent amount of variety as you work your way through the game's 120 levels.

The dialog is incurably cheesy, but not frequent enough to be truly irritating. At the start of the game, the dialog largely consists of conversations between Dante and Virgil. Between each level, you are treated to a snide comment from some unseen critic, whose remarks tend to be humorous in a GLadOS sort of way.

The Inferno used to sell for $2.99 from the Android market, but the price was recently dropped; it's currently available for free. It's not clear if the price drop is a temporary promotion, but it has certainly done wonders for the game's popularity.

Bebbled

Bebbled is a slick clone of the classic Same Game. The user taps matching groups of consecutive marbles to remove them from the field, and points are awarded based on the number of marbles removed.

The game offers a few unique twists on the Same formula. For example, Bebbled will let you flip the playing field by rotating the device. This causes the marbles to consolidate in the opposite direction, potentially giving you access to other groupings. Bebbled uses the phone's accelerometer to detect a flip, which makes the feature feel seamless.

In addition to several "freestyle" modes where the user plays for maximum points under various conditions, there is also a campaign mode where each level has specific requirements, like a target number of points or a cap on the number of moves. These requirements have to be fulfilled in order to proceed to the next level. The requirements generally force the player to think more carefully about the approach and to develop a strategy. It adds a surprising amount of depth to a game that would otherwise get old quite quickly.

The game's artwork has a nice Aqua-like style that gives it a sense of sophistication. Despite the fact that it's a cross-platform port of a game that was originally designed for the iPhone, it feels native and has a decent user interface. It also has some social features, like the ability to compare your scores online against other players.

Bebbled is a very well-executed game, arguably one of the best available for Android. It's available for free from the Android Market.

SpacePhysics

SpacePhysics, by Camel Games, is an engaging puzzle game in which the player must move a ball through colored pinwheels by drawing shapes in the game's environment. If you draw a circle, for example, it could become a wheel that will roll. You can draw lines that act as bridges or become cranks for rotating gears.

Each level has a ball and an arrangement of blocks, gears, and shapes that require the player to come up with a different way to get the ball to the targets. Some levels are easy and others are challenging, but most are thought-provoking regardless of the difficulty level. Coming up with a solution that works can be quite gratifying.

The game's graphics are minimalist by design, consisting largely of glowing lines on a gridded field. The "lite" version, which is available for free from the Android Market, has only 10 puzzles. Users who pay $2.99 for the full version can download the 80-level puzzle pack, which installs to an SD card.