Directions:
1 Click on the game area to initialize the game interface.
2 Type the letter "n" or "N" to start a new game.
5 Score by shooting the enemies.
6 Win the game by killing all of the creatures that would like to kill the universe.
7 Type the letter "q" or "Q" to quit the current game.

Controls
Up--8 or up arrow
Down--2 or down arrow
Left--4 or left arrow
Right--6 or right arrow
Up Right--9
Down Right--3
Up Left--7
Down Left--1
Shoot--Space Bar
New Game--N or n
Music Toggle--M or m
Quit--Q or q

All of the GIFs and some parts of the code came from:
"Internet Game Programming With Java"
By: Michael Morrison.

The source code.