Completed Task 1

Game now works on FireFox without errors
Completed Task 2

Add your name to the welcoming "Alien Invasion" screen (but not the "You
win" or "You lose" screens).
Completed Task 3

Modify the missiles that the player shoots so that they are a little
wider (let's say 6px instead of 2px).
Completed Task 4

Require the player to shoot down each enemy -- that is, if any enemy
moves beyond the bottom of the screen, the player shall lose.
Completed Task 5

Insert a new enemy entry into level 1 to create a set of five enemies
that move left-to-right across the screen while firing missiles at the
player. These enemies should not move downward.
Completed Task 6

Allow the player to also move up and down by using the respective arrow
keys.
Completed Task 7

Occasionally when I play the game and win, I do so by shooting down the
enemy at the end. I rapidly hit the space bar when I play. Currently in
the game, if you win you are shown the "You Win" screen. But, an
accidental space bar event will restart the game. Implement a fix such
that the player does not accidentally continue beyond the "You Win".
Completed Task 8

Currently the game only has one level. Add a second level to the game.
The current level that the player is on should be displayed in the
top-right corner of the game.
Completed Task 9

Add a second player ship. This ship should only be able to move left
(via a key) or right (via d key) or fire missiles (via s key). The two
player ships shall not die if they collide with each other. If one
player ship dies, it should explode and be removed from the game board.
The player should only lose if both player ships die.