Here is the full list of all 20 King Lucas achievements.
Walk 250 rooms.
Finish with 50 spiders.
Use life potion 10 times.
Use the compass in one search.
Find the frog Princess.
Finish with 100 slimes.
Complete the search of 3 princesses.
Walk 100 rooms.
Complete the seacrh of the dog William.
Walk 750 rooms.
Finish with 150 enemies using magic stick.
Finish with 200 enemies using fire sword.
Reach the rooftop terrace of the castle.
Unlock all rooms in one castle.
Kill 200 enemies using ice sword.
Use 50 keys to open doors.
Use invencibility potion 20 times.
Participate in one search in multiplayer mode.
Complete one search before anyone in multiplayer mode.
Organize 20 searchs in multiplayer mode.