The Boktai game from Konami for Nintendo’s Gameboy Advance must be the world’s first sun-powered game. It ships with a ‘solar sensor’ cartridge which uses sunlight (light from a window will do apparently) to charge up the hero’s weapon and fuel puzzles and other gameplay elements. Fascinating eh? You’ll recognise a good player by sunburn marks on the trigger finger I suppose.

‘Although “Boktai” requires sunlight, you can play at night and in other situations when there is no sunlight. However, you must have sunlight when using the “Pile Driver” to purify the enemy boss.’