#1 setting up
#2 create a player
#3 add a gun
#4 fire a bullet
#5 enemy object
#6 spawn enemies
#7 enemy spawn events
#8 move enemies
#9 z ordering
#10 enemy healthbar
#11 enemy healthbar position
#12 repeat enemy healthbar position
#13 enemy hurt animation
#14 code hurt animation
#15 healthbar's z order
#16 healthbar's width
#17 player speed
#18 player wall collision
#19 bullet sound
#20 camera shake
#21 gun shakes