Adaptation Expansion: In the original series, the Turtles eyes turn white whenever they have their Game Faces on. Here it is explained to be a second eyelid commonly found in normal turtles that protect their eyes while underwater, Raphael doing it instinctually when he gets angry.
Smart Animal, Inconvenient Instincts: Raphael is prone to these due to his new turtle DNA. Tang Shen finds him passed out, only to find out that he was just basking in sunlight from a window. Whenever he's startled, he has to fight the urge to retreat into his shell or try eating worms.
Surprisingly Realistic Outcome: Raphael's entire body is different — including his center of gravity — so it takes him awhile to regain full mobility.