TEENAGE MUTANT NINJA TURTLES: THE MOVIE Judith Hoag, Elias Koteas. Directed by Steve Barron. 1990 Rated PG (LIVE/Family home Entertainment tape, 95 min., Hi-Fi stereo, $24.99)

Few parents of American children between the ages of 4 and 12 can claim to have escaped the Teenage Mutant Ninja Turtles. As sheer marketing, the green good guys are up there alongside the guys with the proton packs and, if anything, their mythology is more impenetrable.

So as parents all too familiar with the animated Turtle videos, we'll begin with a selling point: Concentrate a little on this live, feature-length version and you'll at least know who wears what color bandana. Won't that make dinner more fun?

"Teenage Mutant Ninja Turtles: The Movie" is your basic PG action flick with less blood and more reptiles.

Jim Henson's electronically enhanced protagonists, who probably have more facial expressions at their disposal than the actors inside the costumes, are on screen almost constantly. Their wisecracks are funny, and they completely upstage warm-blooded, good ninja K.C. Jones, who fights with sports equipment and is in the story so there's somebody to kiss newswoman April O'Neill with the right size lips (once, chastely, at the end).

Their rodent mentor Splinter is also winningly human. Human bad guy Shredder, who trains JD ninjas, couldn't be more mechanical if the part had gone to R2-D2.

The sewer-locale murk of the lightning translates poorly to video, and Steve Barron's endless fight scenes are dully conceived -- almost any karate-chop-'em-up will give you better. But with 4-to-12s you don't want better,because better means cracked bones and rent flesh.

If you can stomach the tame message -- stay with your real family and don't steal -- there are less entertaining ways to spend time with your kids. The worst thing you could say about this marketing tool is that it prepares children for gorier stuff. The best thing you could say is that it keeps them away from it.