There's an inherent paradox when it comes to difficult puzzle games: you yearn for them to be easier while you're playing, but that would diminish the eventual gratification of solving the conundrums. Metrico is a neat, charming, inventive, and sometimes exasperating example. This side-scrolling platformer sees a silhouette traversing graphs and charts. Different bars on a bar chart react differently to how you move – some rise when you jump, some descend if you run, and so on. As it progresses, your avatar learns to fire on objects and cause platforms to rise or fall. This is done by tapping the PS Vita's touchscreen. On-screen save points are also teleportation points, so some puzzles depend on you zapping to the different parts of the screen. Like many of these games, Metrico ultimately becomes a game of patience. sometimes maddening, Metrico is accomplished and mercilessly addictive – a great idea, well executed. metrico-games.com