This ancient little game, made by Muse Software for the Commodore 64 in 1984, is still completely brilliant to play now and has lost none of its appeal over the decades.
You basically have to pick up passengers and ferry them between ever more difficult destinations. The screens change as you serve a certain number of customers on each level, and the gravity effects can sometimes be tricky to deal with.
What makes Space Taxi great are the responsive controls, the finely-tuned inertia and gravity effects, and the simplistic-but-fun nature of the gameplay. Colourful graphics and solid programming help too.
An obscure retro gaming classic!
More: Space Taxi on Wikipedia