There was a film I had on VCR when I was a kid that must have been from around the 1980s or 1990s. I watched it dozens of times and it had some very large robots that I vaguely think could have been controlled by humans like mechs (I could be wrong). I remember it had some dark elements to it, including a scene with an abandoned city with skyscrapers and skeletons inside them with the massive robots going past. I also remember a scene possibly towards the end in a desert like setting with a cliff on the end that a robot fell off.
I don't remember the robots being particularly humanoid. In fact, I vaguely remember one being almost spherical, possibly with one eye and possible red in colour... It's weird how I can remember the scenes mentioned above, but not other useful details.
I think the style was a Japanese anime type.
I'm struggling, but I'll add more as I remember it! Apologies if this is vague, but it's bugging me and I've done a lot of digging to no avail. Any help is appreciated; apologies for the vagueness.