The bus is rigged with a bomb and you have to rescue the passengers! Keep your speed higher than 50km/h, drive through a road full of traps and rescue the passengers when the police show up.
In Explosion Express you need to take control of the bus and do what needs to be done. The bus is booby trapped, and if it slows down the bomb will explode. Drive in the middle of heavy traffic and help the police rescue the passengers.