As games go, it’s about as politically correct as you can get. Educational, fun and non-violent (the only victims are evil space-aliens), Mechanic Master is a superb way to burn the odd half-hour on the bus – just make sure you don’t miss your stop, it’s really immersive and time will whiz past. This morning for example, I thought I’d have a quick go with my cuppa, sitting outside for my first smoke of the day. The fag burned out untouched. I reheated the coffee twice and still didn’t drink it.

It starts off with simple set levels where you have to build “machines” to accomplish the task – usually getting rid of the aliens. Drop a ball to hit a switch that turns on a fan that blows a balloon that’s attached to a string which pulls a bucket that knocks the alien off the screen. As you progress, things get more and more complex, with more equipment becoming available (although occasionally it’s intentionally misleading and the solution might only require two of the seven things supplied), and getting more interesting, too. The gravity generators are great fun! Progress further and you get to draw free-form solutions to the puzzles, but still within strict limitations. Words cannot explain how complex and engaging this game is. It’s quite difficult to explain. Luckily I found a video. I recommend the hi-def version, as the display is quite small. Hopefully you’ll get the idea of what it’s all about.