Making a space shooter

We're now going to use all the different concepts we've learned to build a full game.

Requirements
This is the bare minimum we need to have a functioning game.
 * Player moving with arrow keys
 * Pointing towards mouse
 * Click creates bullet, moves towards mouse
 * Enemies appear and approach player
 * Bullets touching enemies, both disappear
 * Enemies touching player, enemy disappears
 * Life counter
 * Game over screen

Example
You can see how this simple game works here:

http://4urentertainment.org/phaserexamples/shooter_lifesystem.html

The source code is in the git repository along with all other example code.

You can see a more polished version here:

http://4urentertainment.org/phaserexamples/shooter_polish.html