Here is the full list of all 24 The Light Brigade achievements.
Land 250 headshots. (accumulated)
Finish your first run, start to finish.
Defeat the second boss.
Defeat the Father.
Land 250 gunshots. (accumulated)
Reload 100 times. (accumulated)
Use an enemy's dropped weapon to kill another enemy.
Defeat the first boss.
Rescue an ally Light Brigade soldier out on a run.
Travel 1,000 meters. (accumulated)
Try to fire your weapon without first reloading it.
After death, find your ghost and pray to it.
Pray to the Mother.
Die and be revived for the first time.
Hold onto 1,000 coins at once during a run.
Never miss a shot during a fully completed run.
Every single shot during a fully completed run is a headshot.
Use the wishing well.
Kill an enemy sniper from far away.
Kill an enemy bomber using a grenade.
Kill an enemy priest using magic.
Spend 1,000 gold at a store.
Have a hypnotized enemy kill another enemy.
Cock an ally Light Brigade soldier's rifle.