Deleting pieces is a hassle and sometimes instead makes other pieces that you need to delete... causing you to start the entire level over. Also, I don't think this should be on purpose but some of the levels edges are uneven (i.e. the left side has a wall and the right side has a nonbuildable wall) Eh, 2/5.
 "Tower of Greed"){kind=icon}
 "Death Row"){kind=icon}
 "FWG Bridge 2"){kind=icon}