America - Front
America - Back
The objective is simple: you have 1 life and 1 hit will kill you. Try and destroy as many enemies as possible before this happens.
Each enemy that you destroy will earn you a small number of points. Some enemies will drop coins when they are destroyed, collecting these will earn you a lot more points, 5 times the number of points of a regular enemy. It is important to try and destroy as many enemies as possible, as each one that gets past you will dock your score, so not destroying any enemies for a considerable amount of time might reduce your score of tens of thousands back down to 0!