This season transitioned the franchise into with a heavy focus on character growth and humor.
: The Turtles celebrate their 15th "Mutation Day" and visit the surface for the first time, encountering pizza and the alien Kraang .
: It features a darker aesthetic with heavy shadows and no pupils in the Turtles' masks.
: Reviewers from IGN praised the season for its "fluid, fast-paced" action and its "show within a show," Space Heroes .
: Shredder, Krang, Bebop, and Rocksteady are introduced as the primary antagonists operating out of the Technodrome .