Need help with sprites from Desert Demolition for Sega Genesis

[Shade]

This is proving to be quite a bit more difficult than the cannon, and my unfamiliarity with YY-CHR isn't helping much. The bits and pieces being displayed make absolutely no sense to me trying to assemble them.

For anyone wanting to try, here's what I did.

• Save a state of Desert Demolition (The third level is where the sprites are available, it's an easy game so that's no problem)
  
• Open the state in YY-CHR
  
• Set the graphics format to 4BPP MSX/MD/WSC
  
• Pattern really doesn't matter in my opinion, as long as you can see where the catapult tiles are.
  
• Assemble
  

If someone a bit more experienced with the program can take this up, that would be very appreciated.

Sorry dude.