Looking for the name of a 70's or 80's animated movie

Visually, it's very similar to Wizards and Heavy Metal. It looks as if it was made in the late 70's or early 80's. It's one of those really trippy, pretty damn messed up animations.

I can't remember what the plot was exactly, but here's what I can recall from it.

The bad guy character was a giant brain named metamorphosis. I *think* he commanded what the good guys in the film referred to as "the men of metal". The men of metal were black metal robots with red eyes. They would walk in military formation, and fire lasers out of their hands. When they fired their lasers it looked almost as if they were doing a "seig heil" nazi pose of sorts. The men of metal weren't all that tough, but they advanced in seemingly never ending waves.

The good guy of the film for some reason was put into cryo-sleep to kill the giant brain far in the future. He has to inject something into it with a hypodermic needle. Why he had to do this in the future is beyond me.

In the future world the machines have all but taken over, and all trees and grass is now replaced with never-ending sheets of metal. Basically, a totally machine-based world of some kind.

Also in the future people look like strange mutants of some sort, with missing or extra appendages. Again, no idea why lol.

Oh, and also near the end someone says "the future returns" and 1000's of bird fly in a giant stone head building lol.

That's about all I can piece together of this animated movie. I've searched all over, and I really can't find any info on it at all... But then again it's tough when you don't have the title and google some of the above random phrases, like men of metal, metamorphosis giant brain, etc.

It's not Heavy Metal or Wizards. If you thought Wizards was somewhat obscure, this one has that one easily beat.