Within the core principles of the Backfire design document, the Backfire project was to live off of many of the ideas presented in our biggest influence: Interstate '76. Balance was to be found directly from players customizing their cars, which all had a base stat line and limitations would only be based on a a weight limit stat and the amount of hard points on each vehicle. The hope was to have that system, a location specific damage system more akin to Mechwarrior, and have a simulation and physics driven driving model, to then have a easily recognizable and understandable system for players to pick up and know where they are useful and what tactics will work in their favor or not.
In theory, it was a sound idea: game exploits of the games we were inspired by would be non-issues: we didn't have a Gauss rifle that could shoot further than what could be rendered on screen, and our 'leg damage' equivalent of having a tire shot only affected mobility and didn't take the player out of the game. To add to that, our aiming system was assisted and had no direct precision fire, leading to most tire hits to either be good angling by the player and using level geometry to their advantage. While we never did implement a way to fully customize the vehicles in our final pre-alpha build, we did have a multitude of test loadouts to try these different tactics and see how the driving model handled the weight differences.
Another pillar for the project was to have destructible parts for the vehicles, both to act as a balancing factor for those who wanted to have a large collection of guns on wheels, as well as an easy reference to player state mid-game without the need of health bars or other game staples we wanted to avoid and to allow for more tactics for the player to take advantage of. I distinctly remember one meeting where we had brought up how difficult it would be to play has a car with a speed focus: you would be the most vulnerable on the team, and would have the least fire power. How could you be useful? We then discussed how a fast player could be more focused on taking out previously damaged areas, such as doors or the windshield, generally leading to the killing blow. While this concept remained at the top of the priority list for the whole of the project, we never were able to take the time to implement it and test it.
Ultimately there was some good design forethought on the project in the way of balance and interesting decisions for the player, with some of these concepts coming out in more recent releases such as Mechwarrior Online. (with the change to leg-damage) However, without all of these systems in place, it will be truly hard to know just how well it would have worked beyond what we had on paper, and the number crunching he had done to prototype it outside of the engine.