Here is the full list of all 18 Grapples Galore achievements.
Explode a teammate with a barrel in TDM
Get a bounty
You got 10 kills total.
You won 1 game.
Claim a bounty
Grapple onto another player
You got your first kill.
You got 100 kills total.
You won 10 games.
Win an FFA game with only assists
You won 100 games.
You got 3 kills with only 1 shotgun.
You killed 2 or more players with 1 RPG.
Kill 10 players without dying
Hit multiple players with one burst
Get a kill with every weapon in one game
Hit every shot with a minigun
Kill someone 200+ meters away with a crossbow