Astro Boy: Volume 4 plays out as more of an "Extras" collection, with more one-off episodes than in prior volumes. You don't have to know many of the recurring characters to enjoy the ten episodes collected here, although the introduction to Astro's sister, Zoran, in the previous volume is a must. A return performance from the angry robot Astro battled in the first volume is the subject of "Atlas Strikes Back," and a new villain is introduced named Rock. Rock is featured in the combined episodes "Shape Shifter" and "Firebird," both of which feature some awesome, suspenseful action. Rock is a good hybrid of previous villains like Tenma and Skunk; he has the intensity of Tenma, but isn't afraid to roll his sleeves up and do the kind of dirty deeds that we've seen from Skunk. Unlike Skunk, Rock thinks big - world domination big - and actually seems capable of executing on his plans.
There are more instances on this volume of content that some parents might find too intense for younger children. Some scenes from the first two episodes are especially spook-inducing, bringing ghouls and ghosts into play with a rather graphic treatment. We're not talking the extreme effects present in modern anime, or anything, but images of (fake) dead bodies and other hellish icons in a theme-park setting might set a few impressionable youngsters back on their heels. The out-of-sequence episodes aren't that big a deal by this point, since we've suffered along throughout thirty other episodes, but it especially isn't a problem on this volume. The more we see of this old Astro Boy the more we like, so it's with a little angst that we acknowledge the fifth and last DVD in this collection is coming up next.