When watching this you must understand when it is from.
This is a classic anime, from the director of Akira and Black Magic M-66, and from the era in Manga where you got greats like Ninja Scroll, Battle Angel Alita, and Madox 01.
If you liked any of those then you should like this. If you haven't heard of these then you should really look into them.
The artwork is to me classic, but to others, more fond of the CG graphics of anime today, it may seem dated.
Finally the Film itself. The story seems zany, but its very funny if you settle into it. the story is not so simple as to be childish but it doesn't take a genius to work out. That's what makes classic anime, well, classic.
One thing I must point out that has been mistranslated for years is the name. Roujin Z. Rou-Jin. It means "old man", not "plan". I believed it to be "Plan" after I watched this with the original subtitled name but this must be mistransliteration, as "plan" in japanese is in fact ke-i-ka-ku. I think this is more to do with making a valid english name rather than being true to the original, as old man Z makes no sense in english.
I really think this is well worth a watch, I've had it on video for years and have been trying to get a copy on DVD for a while now, but of course R1 DVD's aren't so easy to purchase.