• Enemy targeting logic in place, tied into difficulty level and enemy type (Saucer is the larger enemy, UFO smaller). If the accuracy value (in list below) is greater than a random number (0-63) then the enemy shoots at the ship, otherwise it selects a random direction. Looking at the list, a UFO on normal should shoot towards the ship 25% of the time

  	   Saucer   UFO  Accuracy/64
  kids	 0	   0	   0	  0
  easy	 4	   8	  6.25%  12.50%
  normal   8	  16	 12.50%  25.00%
  hard	 12	 24	 18.75%  37.50%

  
  

• There's now 32 shot directions for the enemy instead of 16.
  
• For testing, set Right Difficulty to A to have enemy always shoot at the ship.
  
• Revised the UFO appearance to be based on the difficulty level (it would previously show up after 7,000 points):
  
  • Kids - appears after 50,000
    
  • Easy - appears after 25,000
    
  • Normal - appears after 10,000
    
  • Hard - appears after 5,000
    

  [*]updated menu colors

  [*]fixed ball to be white again so shots are more visible (it was back to black after the revised two-color 48 pixel kernel routine).

ROMs

spacerocks20120517_NTSC.bin

spacerocks20120517_PAL.bin

Source

spacerocks20120517.zip