The Crimson Map Pack Add-on for Halo 4 has 8 achievements worth 250 gamerscore.
In Crimson DLC matchmaking, kill an enemy with melee when landing from a Man Cannon.
In Crimson DLC matchmaking, shoot an enemy who’s airborne from a Man Cannon.
In Crimson DLC matchmaking, score the killing blow on a Mantis.
In Crimson DLC matchmaking, board an enemy Mantis.
In Crimson DLC matchmaking, kill 20 enemies using the Mantis' stomp attack.
In Crimson DLC matchmaking, kill a player while airborne from a Man Cannon.
In Crimson DLC matchmaking, kill 20 enemies with a detached Machine Gun Turret.
In Crimson DLC matchmaking, get a kill while airborne in a Warthog.