Here is the full list of all 42 Midnight Ghost Hunt achievements.
250 Reaper Kills
100 Shoves
Unlock every cosmetic in the game.
Taunt 250 times.
Unlock 25 different cosmetics.
As a Ghost, taunt 25 times in one game.
Get 100 headshots as a prop.
250 Spectral Cannon Kills
Win 100 games as a Hunter.
Win 100 games as a Ghost.
As a hero prop, kill 10 hunters.
Kill 100 Hunters.
As a ghost, possess 1000 props.
Kill 100 Ghosts.
Get 5 Aces
Get 10 headshots as a prop.
Win 10 games as a Hunter
Kill 10 Ghosts.
Kill a team of 4 by yourself
Kill 10 Hunters.
Win 10 games as a Ghost
Unlock a single cosmetic
Won first game as a ghost.
Won first game as a hunter.
Get 100 kills as a Lamp.
As a hero prop, kill 100 hunters.
250 Project X Kills
250 Flamethrower Kills
250 Frostbite Kills
250 Ghostsmasher Kills
50 Riot Shield Kills
250 Sledgehammer kills
250 Harpoon Bazooka Kills
250 Grenade Kills
250 C4 Kills
100 Doppelganger Kills
100 Telekinesis Kills
100 Corruption Kills
100 Poltergeist Kills
100 Miasma Kills
Achieve all loadout specific achievements
250 Salt Shotgun Kills