Conan

As soon as you can, purchase the Piledriver and Back Breaker moves; these are easiest grapple moves to perform.

To do a piledriver press B to grab a small enemy, and then X to execute the pile driver.

A back breaker works just like a pile driver; just press Y after grabbing an enemy.

Since there are lots of small enemies in the game, this achievement is easy to get. If you want to get the achievement in one place, the giant squid boss fight will provide endless streams of small weak enemies that you can perform grapple kills on.

For this achievement, it asks you, the player, to perform fifty grapple kills.

I earned this achievement while I was fighting Graven in the last phase of turing the dais, surrounded by a bunch of oilmen. I would roll inte one and somehow either do a piledriver (B, X) or backbreaker (B, Y) and it would keep them at bay while I did it. One after the other, I would slay them with those grapple kills, so once I got my 50th kill, the achievement unlocked. That's what you need to do in order to earn this achievement.

If you want to make it simpler for yourself, complete the game on King difficulty, turn on Invunerability, then make your way to the Giant Squid boss battle in the game. At some point, during the battle, it will switch tactics and change the crewmen into oilmen. Ignore the tentacles and keep on finding oilmen to perform grapple kils with. You can also earn your other grapple achievements on that boss battle as well.

Have fun and good luck!