Ancient Amuletor (HP)

The easiest way to get this trophy is to use the gunner with upgraded muskets. Just keep switching between the two farthest towers on each side of the gate. Most of the enemies spawn near these two towers and they provide a great vantage point as well for the rest of the level. You’ll have to bounce around quite a bit due to the short range of the muskets but that shouldn’t be much of a problem. When you see enemies approaching either outside tower that is in line with the gate move to that tower to kill the enemies. If there is something you don’t think you can see switch towers until you can see it. Do this for five stages and on the sixth stage the siege engine boss will spawn. Simply unload on the boss’ nose cannon and rear flank to kill it. Be conscious of the enemies that will still spawn, most from the siege engine itself. If you have a skill available use it on the boss. This way you should have the boss killed by the completion of the boss’ first circle of the arena if not faster. Don’t worry about the shots the boss is firing on the crystals there is nothing you can do about this and it won’t matter anyway unless you screwed up somewhere else badly.