Was surprise to see this was drawn by Obata. It looked cool and old school, very different from his other works. The reason is because it was drawn in 1992. Looking back at Obata's art, its evolution is kind of crazy. Sure, his style pretty much solidified halfway through Hikaru no Go and Death Note, but his evolution from Cyborg Grandpa-G till now is remarkable to say the least. Many artists don't change that much over the years. He's truly an illustrator, rather than a "manga artist".
I had a theory on this. My suspicion is that, like other productive artists, he had a lot of assistants and a streamlined process. The process usually evolved to be much more efficient than when they started of, hence the huge change in art. In Obata's case, I suspect he streamlined his creatively process through laying out very rough outline of objects, their location and what detail should go where. This allowed greater contribution of assistants on the final product. This could explain the huge shift over the years as Obata's changing crew of assistants have noticeable effect on the final product. The inception of this theory came from the fact that Obata had a number of very successful pupil, almost unusual, which makes me think he could have given them more control over the final product, accelerating their confidence, allowing them to branch out quickly.