To get the hard badge just place your ball in the corner and take your cursor out off the box and place it outside of the box in another corner. Then when a ball is going to hit yours just move your cursor back into the box. It's just like teleporting.
I don't understand why the driver doesn't just take extra fuel with him. Instead he drives until he runs out, gets out of the car, and pushes it back to garage while being chased by zombies. Then he refuels and does it all again.
Replay level 1 about 10 to 20 times. Get rockets and max them all up. And keep replaying levels till you can max laser. Then Go Kick some ass!! P.S. You can hold down the left mouse button then right click with rockets and just sit back and relax. Kind of like auto-pilot.