Revolution

Revolution is a game that I really wanted to like, and really should have liked. I enjoy logic puzzles, especially ones involving spatial reasoning. And that's all that Revolution is: it presents a partially-assembled gear machine, gives you a toolbox of gears, and leaves it up to you to figure out how to complete the design. And some of the levels require -- or at least allow for -- quite clever solutions. 
 
But there's one fundamental problem that the game just can't get past. It requires placing gears in position. To do that, you drag-and-drop gears from the toolbox onto the blueprint, then drag to reposition the gears as needed. But there's absolutely no tolerance for imprecise positioning; if you're trying to position a gear between two or three existing gears, then you have to drag the gear to exactly the right place so that the teeth of all the gears line up. There is absolutely no 'okay-I-see-what-you're-trying-to-do-so-I'll-snap-the-gear-into-the-position-you're-obviously-trying-for'. But a touchscreen smartphone simply doesn't give you the precision that you need -- especially since your finger will often be at least partially blocking your view of the screen. As a result, levels become 20% figure-out-what-to-do, 80% try-and-try-and-try-to-position-the-gears-correctly. And when the game is scoring you based on time taken and number of moves made, the inability to move gears precisely is all the more frustrating. 
 
A few tweaks to the user interface could make this a four-star game.