5000 or 6000? because 5000 you can jump and kill it with your sword. and the whole point of 6000 so that it's head is out of reach of the sword, so you either have to use a bow or cut off its legs, and if you don't have arrows, spidertron 6000 is impossible to kill with just your sword :P
Both. I think it's a bit annoying when you manage to cut off the legs and they should clearly be destroyed but you still need to finish them off.But for balance, in this case, I think the 6000 should require more shots from an arrow. Or you could have a 7000 that has a shield facing forward so you can't destroy it without cutting the legs off (thus stopping it from facing you and blocking the arrows).