I have to use the big crossbow to shoot the enemies. during the 2nd wave when the dwarf uses the horn i cannot cope with the first troll becos it rushes. I keep losing becos no matter how fast i shoot, they will get past and the green bar is low. I am on heroic level.
i have to be at the machine, howTo improve the kill rate? Then i notice my allies in shit, need to revive so i rush down which gave me no time to rush back up.
Best way to do it is to stay on the crossbow that is on the right. You`ll see the trolls coming inside the hall and be able to get a few shots on them before they come out. Should also splash damage the rest that are nearby. The dwarf is the best character to use for this. Stay on the crossbow and when the other dwarves get mobbed just launch an explosive bolt and clear everything attacking the dwarves. The mage even has a skill simaler that will do massive damage to an area. I have done this on legendary in single player about a half dozen times now and it never fails. Keep trying.