Some TMNT stuff was always meant for grownups.

Teenage Mutant Ninja Turtles 30th Anniversary Special is a collection of different short stories by IDW Publishing to celebrate 30 years since the first TMNT comic. It offers brief history lessons on the comics' background, as well as pin-ups and a brand new story from each major comic incarnation, plus a reprint of an IDW Kevin Eastman tale as an "early Mirage" story. It was released on May 21, 2014.