According to producer Taylor Miller, the goal of the developers was to return to the gameplay style of the original Sega Genesis "Sonic" games, but with new elements such as competition. In designing the stages, Sega provided Backbone with level design maps from all the 2D games as a reference, and Backbone looked to all games up to "Sonic Rush" for inspiration. Building alternate paths—a common feature of the original games—was cited as challenging, with the goal of allowing as many rivalry interactions as possible. In choosing playable characters, Backbone focused on characters who maintained the biggest rivalries in the "Sonic" franchise, such as Sonic and Shadow. Silver, then a new character, was added to "mix things up". One challenge was coming up with the art direction for the game; Backbone sought to maintain the look and feel of "Sonic" while still stylizing the game to stand out. Kazuyuki Hoshino and Hiroshi Nishiyama assisted with art and environment direction, respectively.