If you've played any other game about rotating tiles and connecting power sources, you already basically know how this works. Each level contains one source of energy and a network of other tiles with anywhere from 1 to 4 outlets apiece. Click on the right side of a tile to rotate it clockwise, and on the left for counter-clockwise. Your job is to arrange the available sections so that every space has power and none of your tiles have any unconnected ends.
The catch is that you can only rotate a tile if it already has power flowing through it, which bumps Grid up a few notches on the thoughtfulness index. The choice between rotating left and right is a necessity rather than a mere convenience, since you can easily cut yourself off permanently from half the grid with one ill-considered click.
That's where the wonderful, precious, life-blood-of-my-ancestors, oasis-in-the-desert, significant-other-surprising-you-with-a-sandwich-and-hot-cocoa, beautiful, sexy, irresistable Undo Button comes in. In what is surely the kindest display of humanity this year, Atomic Cicada lets you back up move by move to the very beginning of the level if you so desire, at the cost of only a couple of points per use. Take advantage of this feature by pressing [space], or by clicking the Undo Button, located like the Star of Bethlehem at the top center of the screen.
Analysis: Grid uses the same gameplay mechanic as Loops of Zen and probably dozens of other similar games, most of which employ randomly generated layouts. There is a fundamental tonal difference in Grid's carefully designed levels, though. Each one has its own shape and flow, which may be enough to keep you interested after you've already mastered all the basic solving techniques.
Later levels often feature at least one maddeningly isolated tile off in some corner, sometimes requiring you to re-route the entire level for its sake. Although 35 levels doesn't sound like much, by the end you are essentially solving each puzzle multiple times, and the cumulative effect of using all your tricks to pull together a giant mesh-work of obstacles is an epic sense of achievement.
That said, Grid feels like it should have more variety. I admire its purity—35 levels of nothing but a single power source and five different tile varieties—but it doesn't consider even obvious permutations on the formula, like multiple power sources and immobile tiles. It will only stay entertaining as long as your Frustration Level is less than or equal to your Goal Completion Satisfaction Quotient plus your Obsessiveness Factor, divided by your New Stimulation Requirement Threshold, or F≤(g+o)/S. Which for me was about midway through level 26. Results may vary.
* Now available on Jay is Games: entomology jokes!