In the game, some units cannot be attacked. The bar of the blood of the units disappear. I cannot ask my soldiers to kill them. For human-beings which cannot be attacked, if I put my soldiers near him, my soldiers will kill him automatically (but I cannot ask them to do so manually). Although my soldiers kill them, they will not die. For the wall (maybe for all buildings), even if I put my soldiers near them, they will not kill them. Surely, I cannot ask them to do so manually too. You may get the save game file for further information: http://db.tt/UvhOB29k Thanks for giving me a great game!