Dragon Crystal (Japanese: ドラゴンクリスタル ツラニの迷宮, Dragon Crystal Shirani's Maze) is a video game released for the Sega Master System and Sega Game Gear. Its gameplay derives from roguelikes, with a more intuitive graphical interface and is an 'unofficial' sequel to Fatal Labyrinth.
As the player rides a bicycle one late afternoon, he turns down an alley never before noticed and enters an antique shop. There a mysterious glowing crystal lies on a shelf. Upon approaching the crystal and gazing into it, a powerful force pulls the player in, causing a blackout.
The player awakens in a forest with a large egg following behind. This forest is a huge maze, crawling with dangerous creatures. The player finds weapons and other items scattered around with which to fight the monsters. The only way out is to continue forward, defeating monsters and growing in power along the way.
Source: Wikipedia, "Dragon Crystal", available under the CC-BY-SA License.