Here is a guide on how to get all achievements in Plagueworld in about 20 minutes.
Dungeon
Prisoner
Get into the dungeon prison.
Treausure hunt
Find a secret treasure chest.
Life potion
Find a secret life potion.
Tunnel
Dead trap
Find the body in tunnel.
Wall explorer
Find the secret movable wall area.
Tunnel escape
Get past through tunnel.
Tomb
Marksman
Get the crossbow.
Reptilian
Killed the demon reptile.
Invasion Game Mode
Safe house
Get to the safe house in Invasion.
Demon hunter
Defeat all creatures at village in Invasion.
Written by Trashes