Go to the Balin's Tomb level. Once you get to the part where the Troll comes out, first, attack him. Then press the black button when he tries to attack you. Repeat(while at the same time guarding yourself from the orcs) untill you jump up on the ledge on the perimeter of the tomb. An orc will be waiting for you. Kill it then hide behind a pillar with you bow/throwing axe at the ready. Wait untill the troll slashes a hole in the pillar, the shoot it through the hole. Note: this will only work as long as there are pilars to hide behind. Another strategy is to wait behind a pillar untill the Troll is in mid-slash. Then run to the side and shoot the troll when it has it's back turned, trying to break the pillar. Once you beat this level one time, you can beat it every time.