Is there a way to delete specifically one single pixel of land?
<-x <-y 0 SetLand
Are structures, the blue and red walls deletable through code?
The "blueprint", I think not, the actual Struc may be, but I don't see a command. You could try X Y 0 SetStruc, but...
Edit, rather later: This now exists as SetStruc.
Which of the particle commands can return the particles angle if you will. If it exists
GetParticleMotion returns the X and Y components of the particle's motion. You can do something like this to get the angle in radians (if it gives you the wrong value, try removing the negatives):
<-particle GetParticleMotion neg swap neg atan2