Sonic The Hedgehog LeapFrog Didj Custom Gaming System Educational Spelling Game Sonic The Hedgehog LeapFrog Didj Custom Gaming System Educational Spelling Game. This educational software cartridge is designed for use with the LeapFrog Didj handheld gaming system. It combines classic platforming gameplay with spelling challenges tailored for children in grades 2nd through 4th. • Brand: LeapFrog • Model: Sonic The Hedgehog • Format: Cartridge • Release Year: 2008 • Genre: Educational A great addition for collectors of educational gaming media or fans of the Sonic franchise.