A plethora of puzzle games involve getting from A to B to finish a level, and Propel is no exception. Many puzzle games also hide the exit and make you figure out how to get there, which Propel does on most levels, though it gives you a large bouncing shadow arrow to indicate the direction in which you want to go. And games of this type typically have one or a handful of interesting mechanics you must master in order to solve their puzzles, which Propel does, too.
Propel, however, combines some of the fine motor-skill requirements of the platformer with the logical-thinking challenge of conventional puzzle games. You move left-right with the arrow keys, as in a platformer, but cannot jump; all you can do, really, is roll off the platform and fall. As you fall, you try to avoid obstacles that will kill you, while landing on platforms -- or on arrows.
Arrows are of varying types, but the most interesting ones change the direction of gravity. Suddenly, you're falling left, right, or even up. But things are even weirder; the handedness of your arrow keys changes with the orientation of the arrows, so you're often left wondering which way the left and right arrows will move you, and often getting it wrong and slamming into a killing obstacle.
Then there are arrows you can bounce up and down on, arrows that propel you faster, and so on -- along with 'bonus point' features in most levels that are the devil to get to.
With stark neon graphics and excellent danceable techno from Martyn Corbet, this is quite an engaging -- if often frustrating -- little game. There are quibbles, of course; the 'bonus point' features are meaningless without, you know, actual points, and a 'replay' feature so I could be sure exactly how I died before playing again would be nice. The fact that there's no ability to save games, and that the game doesn't track on levels you've unlocked when you quit, is also annoying. But the unlockable level editor is a good feature, albeit it would be nice if there were a discovery system allowing you to browse and play others' levels.
