changed laser sfx
added bg_img and changed sprite colours to stand out more
added kill count, changed font and changed game speed
game now renders level number
levels changed
kill count now carries over levels
kill count resets to zero on death
endGame and winGame now display total kill count
changed start key from space to enter

stops player from automatically firing when the game starts
high score added
alert box appears when there is a new high score
saves high score in local storage

the high score is saved until the user clears their browser cache (or
cookies, depending on where the browser saves it)
changed name to Planet Invasion
bug fix

fixed bug where the score would always show as 0 if the player moved
into a missile
updated level data to make the game challenging
README updated
Merge pull request #2 from LewisN/experimental

Experimental