Hm, looks sweet! One gripe about super-realism - usually "fun" stems from unexpected game-play variations (and decreasing entropy). In Quake 3, it was the rocket jump. In sandbox games, it's, well, the sandbox. This is also why finding (physics) bugs is so fun. Here, however, I'm not sure if one will be able to do interesting things. Can you, for example, smash half the truck away and be left with a "bike"? Just random destruction seems like it will get old fast.