If you place a bomb in front of a Dodongo but not so close as to be swallowed, the dino will freeze when the smoke blasts its face. It is then vulnerable to the sword and it is GUARANTEED to drop a bomb refill. This seems to be easiest to achieve when the Dodongo is moving side-to-side, possibly because it is a bigger target in those directions. As for the Darknut Stab Exploit, find a choke-point, face down, and spam the sword button. If you're immediately above a no-walk tile the Darknuts will not be able to approach from that direction, so they will always be vulnerable to your sword. The repeated stabbing ensures they cannot knock you out of the choke-hold (since Link cannot move while attacking). Finally, if multiple Darknuts swarm the spot only one of them can hurt you at a time (thanks to temporary invulnerability).