In single player mode, you can get more
firepower and more lives by setting the controls of both players to be
exactly the same. For example, player one: Fire=Space and player two
Fire=Space. By doing this, you can focus on one blob, but the other blob
will move with and shoot with you. This kills more enemies and gets you
to higher levels. A good idea is to set the special key to a different
button for each player so that you can get double the cow bombs.