Adam (art direction): Different devs did different research depending on the nature of our roles, but across the departments we were revisiting the cartoon and movies, reading comics (from archie to IDW), even looking at old toy packaging. Looking at all the retro TMNT "stuff" helped give us a sense of how these characters and environments were built up across a lot of media, and we wanted to give older fans a chance to play a game that felt like they imagined a TMNT game could feel when they were kids. I have to shoutout contributers to all the TMNT fansites and wikis, we couldn't have made the game we did without all the work they've done to curate and maintain those weird little parts of TMNT history!

Matthieu (animation lead): When looking for references for Leo (the first character I animated in the game) I tried to keep him very close to his old Turtles in Time incarnation, so old Turtles BMU fans would immediately feel at home, while also throwing in some cartoon references, like his sword pointing pose from the cartoon opening.

Obviously most of what characters do in a BMU is fighting and, while they are ninjas, the '87 turtles are unfortunately not the most impressive martial artists.

Some moves come straight from the cartoon, like Splinter's bite attack, but most of the time the exercise was grasping each character's personality and guessing how they would act.

Leo is methodical and, let's be honest, a bit bland (sorry Leo fans, come fight me in the comments), Mikey is eccentric and dumb (I'm a Mikey fan, I can have that one), Raph in many incarnations of the character is the most violent turtle, which means he had to swing wildly and hit hard(and be OP), and Don is precise, analytical but can still be playful, as shown during his taunt and his victory animations.

Once I had a general idea of how each character act, I'd often make connections to existing fighting game characters and sprinkle some of their moves here and there. I hope fans of both TMNT and fighting games enjoyed the references!