When Bédard joined the project , the game focused on the 2D – 3D mechanic and did not yet have open world ambitions . He coded the game in Microsoft Visual C # Express and XNA Game Studio Express . His first task , the level editor Fezzer , was coded from scratch in XNA and inspired by SketchUp . Bédard also wrote the game engine , Trixel Technology , which turn 2D tiles ( " triles " ) into sides of a 3D cube pixel . The engine track player @-@ character Gomez in 3D space even though the game behave as a 2D platformer . Bédard also built the game to resolve collisions when converting between 3D and 2D space .