Peter Chung's TMNT designs
 

Yep, "the Aeon Flux guy" is the reason the original TMNT intro and first season looked so cool:
https://www.instagram.com/peter_k_chung/

April O'Neil in Action!
https://www.instagram.com/p/CU_x7aFrtGA/
http://i.imgur.com/odoElZz.jpg

Additional images SPOILER'd for large sizes:

Pre-Mutation Rocksteady and Bebop (unused concept)
https://www.instagram.com/p/CU_v54dLgr5/


Splinter/HamatoYoshi
https://www.instagram.com/p/CU_w-JVLIw0/


Shredder/Saki
https://www.instagram.com/p/CU_xSjfLRbk/

SPOILER'd for large images.

Turtles in Disguise
https://www.instagram.com/p/CU_wP9SLemR/


The Punk who would become Scrag
https://www.instagram.com/p/CU_vqNYLcZd/


Zak the Neutrino
https://www.instagram.com/p/CU_wGINLzZe/


April O'Neil's head turnarounds
https://www.instagram.com/p/CU_xxEwLdXm/


April's expressions
https://www.instagram.com/p/CU_xluIrenR/

Wow, thank you for sharing! I would be curious to see even more of his turtles drawings.

Cool to know that he was the art director of the original series. The art also reminds me of the original coloring books.

I also thought "isn't that the Aenflux guy?" I'd definitely love to see a TMNT short made by him. It'd be all kinds of crazy.

Neat to know that he designed Krang's body as a joke, not knowing the series would get so popular.

Yes, definitely. The Random House books followed these designs very closely, especially the first two books by Fernando Fernandez.

What a great post....
I love Aeon Flux too.

Rocksteady’s human design was going to be a flaming homosexual? That’s a gay character design if I ever saw one.

Neat! Thanks for posting them!

But that one pair of images of April though... lol Calm down, Ariel, it's just a spoon.

I see someone is too young to remember anything of the 80s punk era.

Amazing.

Funny how Rocksteady design has completely changed between this and cartoon itself.

Shredder looks more like Mirage incarnation. I wish there were some sketches of Krang and some other characters.

Also, I've read there was another character designer, before Chung was brought to the series. Is there any more additional information about that?

I think I've seen the final Shredder design somewhere else.

Thanks for sharing these images. The alternate Bebop & Rocksteady designs might have worked if they were ever approved.

It would appear that Chung liked the design for April O' Neil.

I don't mind the Human designs Bebop and Rocksteady much. Once Shredder sprays the mutagen on them in Enter the Shredder, it is all over.

Very cool. I really dig Aeon Flux because it is so dang bizarre and otherwordly. It's cool to see his take on TMNT. If only he could do more with the brand.

Cool to see that he storyboarded the original opening theme as well. Still the best theme in my opinion.

I'd take that opening intro over pretty much the entire series, for the animation quality. I find it to be gorgeous looking. I agree, it's really cool to learn he was behind it.

I'll include the other turnaround photos of April here with links to the original posts, to make them easier to find for future reference.

April facing front
https://www.instagram.com/p/CU_yqjwLhCq/


April side profile
https://www.instagram.com/p/CU_yTtVriXR/


April's backside
https://www.instagram.com/p/CU_yIu1LtLD/


April in Action (higher resolution)
https://www.instagram.com/p/CU_x7aFrtGA/


Chung also comments about his design on Krang's Android body:

Peter Chung posted his original storyboards for the opening sequence!

https://www.instagram.com/p/CWCv5o4L6Qy/

Storyboards Part 2
 

https://www.instagram.com/p/CWCvqjGLW4z/