Sometimes, the quality of a game is measured by the degree of frustration it can create while still drawing you back to play. During my first half hour with Candy Train (PopCap, free), I could punched my finger straight through my Touch at least once per minute. It has that maddening frustration that can only come with cute and colorful games, as though their childlike qualities mock your inability to play them successfully.
Candy Train is a remake of an old Java title that was still floating around on the internet until recently. (I can't find a current version, so it's probably been removed to keep attention on the mobile port.) It is insanely addictive, perhaps because you always seem so close to getting it juuuust right, moments before you fail completely. This is really just a train pathing game with a tile-switching mechanic, but it’s one of the most appealing free puzzlers to appear on the iOS format this year.
The game is played on an 8x8 grid comprised of tiles representing different track configurations. There are curves, double curves, straightaways, and crossings. Tiles are turned by tapping, thus reorienting the track configuration. In this way, you create a path for the train to follow as it collects points and gathers new cars filled with candy and other treats. If your tracks don’t connect, the train crashes and the game ends.
After all the cars on a map are collected, you attach a caboose and steer the train to the switching point for the next level, where you begin again with more cars. Aside from changing the train speed from slow to fast, there are no other controls.
The normal mode is tough enough, but the expert mode is maddening (in a good way). This is a tricky game to get into, but great fun once you start to master it.