Super Game Boy Player's Guide was a guide book sold with an issue of Nintendo Power around the release of the Super Game Boy. It contained six pages on Metroid II: Return of Samus showing key points in the game, with codes that could be used to enhance the look of the game for those moments. The game itself also appeared on the cover and several other pages.
The guide refers to Metroids as "Space Parasites", the Galactic Federation as the "Intergalactic Federation", the Bomb item as the "Bomb Generator" and Energy Tanks as "Energy Containers" (in one instance). It also says that SR388 is in the "Game Boy star system", and suggests that the Metroid mutations are due to gamma radiation from the planet. In the introduction, the guide states that "It's only a matter of time before some evil mastermind decides to lead the Metroids in a revolt."
This gallery shows the various codes that the guide suggests.