2d shooter tutorial

My plans for modification are to add 3 complete levels, with well placed enemies and progressive difficulty.  I also plan to add a new enemy type that runs away from you.  Because it is harder to track down, it will be worth more points.  This will cover the graphical part, as I will be drawing the enemy myself, and the gameplay modification, as I am adding a  new enemy type.  The design modifications will be fulfilled by creating new levels of increasing difficulty, and using the new enemy to do so.