Great game.
I've only played the original once, but it was fun, and this is better. But, like other people have said, the whole fuel concept isn't very realistic(I guess the bouncing off of helicopters isn't very realistic, either, but still.). You don't really have enough fuel to get a 75 combo(my fuel was almost gone getting 50), especially when the missiles are keeping you above all of the planes. And somehow bouncing off of helicopters uses fuel. There's no way to increase your fuel without beating the level, and if you run out of fuel, you blow up, even if you're in midair. I pretty much agree with tomthecool. It's a great game, though.