iPhone, id Software, £2.99

Trips down memory lane can be cheaply bought. Wolfenstein 3D, which costs an extremely reasonable £2.99 from the App Store, is a mobile version of the unforgettable FPS that hit PCs in 1992. All 60 of the original levels are here in all their Nazi-slaying glory and even if you were a Wolfenstein demon back in the day, I defy you to remember all the fiendish twists of the titular castle. The graphics show all of their 17 years, but for sheer playability, and the sheer joy of rediscovering a truly genre-defining adventure, Wolfenstein 3D is very hard to beat when gaming on the go.