Just as a general idea and not say something bad about your code:
If all "enemies" change their y-coordinate simultanous there is no need to change each y-field. Just have a global moveY-field within the TEnemy-Type and change it when needed. When drawing/updating/calculating you easily add moveY to the y-field [ drawimage(self.x,self.y+self.moveY) ].
Although this seems unnecessary for a list with 20 objects, but imagine something like "sidecrolling effects",instead of moving each tile of a level you just "displace" the view with changing only one variable.
bye
MichaelB
If all "enemies" change their y-coordinate simultanous there is no need to change each y-field. Just have a global moveY-field within the TEnemy-Type and change it when needed. When drawing/updating/calculating you easily add moveY to the y-field [ drawimage(self.x,self.y+self.moveY) ].
Although this seems unnecessary for a list with 20 objects, but imagine something like "sidecrolling effects",instead of moving each tile of a level you just "displace" the view with changing only one variable.
bye
MichaelB