Here is the full list of all 14 Weapon of Choice achievements.
Beat the Evil Sun.
Use the SMOKE WALK for the maximum time.
Rescue every Solus Operative.
Rescue someone and get them out of the level.
Shoot 5 birds.
Kill 10 aliens while hanging by the SPIDER PACK.
Beat all branches.
Beat level 1 (Mountain Village) in under 1 minute and 10 seconds.
Collect all MBG pies.
Use Xerxes to reach a boss without touching the ground.
Kill 10 enemies with the SPIKE LIFT.
Beat a game branch only killing bosses.
Beat a game branch without activating death-brushing.
Beat all branches in MEGA-WICKED difficulty.