Looks can be deceiving. This puzzle game seems so simple at first, with gentle, easily solved levels that seem to move on very gradually. All you have to do at the start is direct trains into the correctly coloured station. New twists are introduced slowly, and it all seems quite civilised. Then it suddenly turns on you, throwing everything in together, and you realise what a clever game it is. The difficulty curve is perfect, ensuring that you're never left stumped, but the puzzles might take some serious thinking (and some inelegant solutions the first few tries). By then, you'll be frantically planning how to switch the colour of trains, swap them around, and generally wondering if this explains the overall state of the UK's train service.