When I was a child, I used to play with one of those Labyrinth games where you turned the knobs to tilt a platform and roll a marble around a series of holes. I was always terrible at it, so I used to take a handful of larger marbles and strategically plug certain holes before I made my runs. However, I never would have imagined using catapults to fling the marbles, or blocks of TNT to knock pieces out of place. I'm sure my mom wouldn't have approved of the TNT. In Cat Daddy and 2K Play Games' GridBlock, you've got to use TNT, liquid nitrogen, and teleporters to slide all of the cubes into place. GridBlock is an action puzzler that takes advantage of your device's accelerometer to make a tricky tilting challenge.
At the start of each level, you'll find one or more loose cubes that can be slid around the screen by tilting your device. The goal of each level is to cover each of the target squares on the floor of the grid with a block with the matching color. When a valid block passes over a target, it locks into place, and can only be dislodged by explosions. Blocks are either red, green, or blue, or some combination of these colors, with one color on each side; only the color on the top of the cube is regarded when matching targets. If you want to switch the orientation of the cubes, tap the screen while sliding to make the cubes "flip" and rotate in the direction of the movement. There are also wild blocks that can fit into any colored target, but they must be wielded carefully, as there's often a limited number of ways cubes can be shuffled around to still produce a victory.
In the initial levels, you're only given a handful of cubes and asked to slide them into their proper places, but by collecting tokens, you can unlock more levels that carry new devices to help (or hinder) your progress. Blocks of TNT can dislodge extra blocks and come in handy when you're given only one or two cubes to start, but have to fill eight targets. Frozen blocks can slide with less friction, which is helpful when you need to move one cube away from a pack, but makes it trickier to maneuver that block through obstacles. Be sure to watch out for converters on the floor of the grid that can give your cubes these properties, and be sure to hit them with the right timing, since they sometimes move around!
While it's tricky enough sliding eight cubes at once so that they avoid obstacles, another challenge comes in the form of managing your cube count. Some converters require you to sacrifice a cube (such as the TNT converters and the ghost tokens), so you have to carefully plan where and when you let your blocks hit them. A level will automatically end if you run out of available cubes to slide around, or if you run out of cubes with sides of a certain color, so try to avoid such dilemmas.
Analysis: GridBlock is not a simple game by any means, but it's presented in a way that is accessible to most skill levels. In each nine-level set, in each of which at least one new concept is introduced, you're given one level that serves as your "practice run", then you're immediately thrown into much trickier territory in the subsequent levels. Most levels start by showing you a small hint as to how to proceed with the level, so you're never completely left to fend for yourself. You have plenty of time to finish each level, so slow down and evaluate all of your surroundings before you rush headlong into a trap. Even in the later stages, when several different concepts come into play all at once, you don't feel overwhelmed if you take the time to analyze the level before you start. Unfortunately, there is no colorblind mode for those who have difficulty working with those colors, so the use of a primarily red/green/blue color scheme may render this game unplayable by some.
One flaw in this game that can become irritating rather quickly is that the game has a hard time settling on what constitutes "flat". You may find, as a level starts, that all of the blocks quickly slide to one edge as though you were tipping your device in that direction, even if you weren't. Sometimes, the ideal "level" position is parallel to the ground, sometimes it's tipped up toward you by some degree. There are very few instances where this unpredictable slide can ruin a level right from the start, as it's easy to correct the tilt once you see how the blocks start moving, but it feels like an issue that should have been ironed out before release.
Another quirk, albeit a minor one, is how this game regards the physical nature of cubes. Even though you're playing with loosely-floating blocks, they still remain flat in relation to the edges of the screen (which is good, because otherwise it would be impossible to perfectly aim a cube in a one-cube-wide gap). However, this permanence of orientation seems to disappear when you jump the cubes in some tight areas. A cube might become lodged between a fixed block and a wall (with one edge pointing down), and it takes a bit of jimmying to get the cube out of that spot (I think my technique involved tilting and tapping at the same time). It's not a horrible bug, but in moments where you need to stick to finer movements, it can be a hassle.
These bugs shouldn't overshadow the fact that GridBlock is still a solid game, and a good challenge to boot. Even when a level seems impossible, a bit of thinking will reveal how to beat the level, or possibly even grab the tokens as well. Just take your time, slide with care, and make sure your mother doesn't walk in when you're propelling your marbles across the room with the treadmill.
NOTE: This game was played and reviewed on an iPhone 4. Game was available in the North American market at the time of publication, but may not be available in other territories. Please see individual app market pages for purchasing info.