Flamethrowers (in a fuel starved world, no less)
I think you're not watching the right movie. The Mad Max world is starved of a lot of things, especially water, but Guzonline is definitely not one of them. That's actually what they call it. It's about the only thing they have. They trade it around at will and drive vehicles which burn through it a great deal. Heck there's even a line in the movie where they take the piss out of how much fuel and nitro they have burnt through pursuing max and then shrug it off.
What little plot it had perfectly describes the results that you complain about.
- Person strapped to the front of the car, because he had to be. There's no space in the cab or the tray for your blood supply.
- Doing battle around a tanker? Well the War Machine was a vehicle specifically kitted out to fend off attacks so it stands to reason they are battling around it, and without giving away too much I wouldn't worry about it blowing up given it never actually makes it to the refinery to get filled.
- The vehicles resemble what would be hacked together if the world suddenly went under and the only thing on hand was older cars to weld together. A lot of effort was put into designing vehicles which could legitimately be made from cars of only that era. Aside from armour plating, some spikes on the tires, and that one car with spikes all over (a homage to the Echidna, an Australian ant-eating mammal), most of the cars are pace cars designed to get you close enough so you can throw grenades at your target.
- Fireworks? Got a better way of signalling in a world without electricity? Though they do use semaphore towers between fixed places, the the fireworks were used for communication.
Don't judge a book by it's cover. It has very real stunts, few special effects, is definitely not overhyped, is not a rehash (and has nothing to do with previous Mad Max films), and I would have to say is anything OTHER than dime-a-dozend Hollywood shitfests which are coming out at the moment. It's a movie narrated beautifully by action and not dialogue.