Here is the full list of all 24 Mini Ghost achievements.
Find all Twitch Friends
Kill boss zone 3 receiving no damage from it
Kill boss zone 2 receiving no damage from it
Buy everything available
All items in inventory
All hp bar unlocked
Beat the game without dying.
Beat the game in less than 45 minutes
Beat the game without using secondary weapons
Beat the game without dying or being assisted by doctors
Beat the game
Kill boss zone 1 receiving no damage from it
Find secret room
Obtain card 4
Destroy boss zone 3 with a mine
Find night vision goggles
Obtain card 3
Destroy a boss in less than 40 seconds
Destroy boss zone 2 with a laser
Destroy boss zone 1 with a rocket
Obtain card 2
Reach boss zone 1 without killing any monster or being damaged by them
Pick up any item in less than 16 seconds
Change a friend's character while he/she is playing