Finders Keepers is a computer game written by David Jones and the first game in the Magic Knight series. It was published on the Mastertronic label for the ZX Spectrum, Amstrad CPC, MSX and Commodore 64 in 1985. It was published in the United Kingdom at the budget price of £1.99.
Magic Knight has been sent to the Castle of Spriteland by the King of Ibsisima in order to find a special present for Princess Germintrude. If Magic Knight is successful in his quest, he may have proved himself worthy of joining the famous "Polygon Table".
Gameplay in Finders Keepers is markedly different from that in the other Magic Knight games which are essentially graphic adventures with a few platform elements.
Finders Keepers is basically a platform game with some maze sections. Our hero starts in the King's throne room and is transported, via a teleporter, to the castle. The castle is made up of two types of playing area: flick-screen rooms in the manner of a platform game and two large scrolling mazes. On the ZX Spectrum, Amstrad CPC, and MSX these are "Cold Upper Maze" and the "Slimey Lower Maze"; on the Commodore 64 they consist of "The Castle Gardens" and "The Castle Dungeons".
An additional part of the gameplay is the ability to collect objects (found in both the rooms and the mazes) scattered around the castle and sell them for money. Some of these objects can combine or react to create an object of higher value (for example, the 'bar of lead' and the 'philosophers stone' react to create a 'bar of gold'). Both the amount of money Magic Knight is carrying and the market value of his inventory are displayed on-screen. The buying and selling of objects is done with the various traders who live in the castle.
The Castle of Spriteland is full of dangerous creatures who inhabit its many rooms as well as both of its mazes and collision with these saps Magic Knight's strength. If he loses all his strength then he loses one of his four lives.
Finders Keepers was followed-up by three more Magic Knight games. These are Spellbound (published 1985), Knight Tyme (published 1986) and Stormbringer (published 1987).
Source: Wikipedia, "Finders Keepers (video game)", available under the CC-BY-SA License.