This is that rarest of beasts, a sci-fi movie from an era when we didn't get that many of them which has absolutely no cult following whatsoever, even of the ironic "so bad it's good" variety. Why? Because it's just plain boring. Or, in the modern parlance, it's as meh as you can possibly get.
In the wake of World War III, a handful of survivors must cross the radioactive desert which is all that remains of America in a sort of heavily-armed monster truck bendy bus that looks as though it was designed by Gerry Anderson which for some unexplained reason they happen to have. Along the way they must contend with murderously degenerate hillbillies, unstoppable hordes of armor-plated flesh-eating cockroaches, giant scorpions, and weather gone mad in a very seventies psychedelic kind of way (though not the mutant plants the synopsis promises us). How can a movie with a plot like this possibly be dull?
But alas, it is. B-list actors and a C-list director do nothing remotely interesting with the premise. The perils they face are either underwhelming or over in a very short time, apart from the crazy weather, which is frequently represented by clips from other much more expensive sci-fi movies such as "When Worlds Collide" (World War III is of course a lengthy montage of grainy stock footage). Mostly they drive across an empty desert in which those giant scorpions which were established as a major threat very early on never show up again, presumably because the special effects were more expensive than the normal-sized cockroaches which cause them far more trouble. Along the way, they pick up a slightly annoying kid, a very annoying lady who screams and has to be rescued a lot and has a silly French accent, and do a great deal of essentially good-natured and very poorly acted bickering.
And that's about it, really, apart from the worst deus ex machina happy ending you'll ever see. Everything potentially interesting, including the massive firepower of the Landmaster amphibious all-terrain battle-tank, is horribly underused, and instead we get endless footage of the sky turning a funny color and putting on a groovy light-show. Notable only for being yet another abysmal post-apocalypse road movie nobody cares about which George Miller borrows from extensively in "Mad Max: Fury Road" just so that obsessive B, C, and Z-movie addicts can play spot the obscure pointless reference. Don't waste your time.