space invader

#1 game window

#2 game window icon

#3 draw player

#4 movement concept

 #5 keypress event

#6 move spaceship

#7 create enemy

#8 enemy move

#9 background image

#10 create bullet

#11 fire bullet

#12 adjust bullet movement

#13 bullet collision

#14 respawn enemy

#15 multiple enemies

#16 move all enemies

#17 show score

#18 add game sound

#19 Game Over