in those lines where the players can cross through, but not the monsters, players can kite the monsters there and let the trojans kill the monsters. i'm presuming unintended.

in those lines where the players can cross through, but not the monsters, if they're clumped together at the gate, it's possible for the trojans to push the monsters through to the other side.

in those lines where the players can cross through, but not the monsters, the line is supposed to prevent rocket puppies rockets. but if the rockets are going through their, "turning," animation as they come to the line, they'll pass through.

zombie resurrect totems can be used to stop the wheels that come at you; don't know if intended or not.