Yeah they rule. I actually think the regular enemies are even better. Tons of great designs, great silhouettes, great poses, way more shading than you should be able to get out of three colors. Rarely the first thing you'd think of if you sat down to draw the thing in question either, they just ooze style.

I looked up Kazuko Shibuya's later work and apparently she did monsters for Terra Battle (who has ever heard of this) and she's still got it. Look at these random monsters I got from clicking around on that wiki