Sliding-block puzzles have been popular for ages, even in the computer age. With a simple 2D layout and limited motion, they're perfect for software, and you can play all kinds of free Flash versions online. But the Android incarnation of the ancient favorite may be the best one yet: Small, easy to play, and perfect for thumb-swiping. Unblock Car is a free Android app that puts an all-too-familiar spin on the classic sliding-block puzzle game: an overfilled parking lot with your car at the very back. Your task is to move as few cars in as few steps as possible to free your path to the exit. More cars fill the lot as you move up through its four levels and thousands of game combinations. You can change the theme to futuristic vehicles, colorful toy cars and trucks, or blocks inscribed with ancient glyphs. We played it in Android's Ice Cream Sandwich edition on a smartphone.
In any of its themes, Unblock Car's interface and layout make great use of high-resolution touch screens. There's a brief tutorial under the Menu's Help button, but this is a sliding-block game, not chess, so most users will be able to figure it out. The Options button let us turn the volume of the sound effects and background music up or down with sliders instead of on-off buttons (something all games should offer). Tapping Play gave us four levels, Easy, Casual, Normal, and Hard. Of course, we chose Easy since it's tough to deliberately choose the worst possible parking space, and we needed to build up to it. The counter starts as soon as you press Play, and pausing hides the parking lot, so you can't spend too much time gazing. After a few games, we'd cut our number of moves in half, and improved our time. You can undo your last move, reset the game, and get clues, too.
It gets harder to extricate yourself from your parking nightmare as the stages increase, and your move count and time will both go up. But this brain-training game is easy fun for all players.