Here is the full list of all 20 Monster Girl Club Bifrost achievements.
Made 300 clients into happy campers
Raised a queen
Used up 50000 of clients' energy
Made 100 clients into happy campers
Fulfilled 20 escort requests
Cleared Normal Mode
Cleared Hard Mode
Cleared Expert Mode
Cleared Hard Mode without any new game plus bonus
Owned 3 "Maid Knowledge" girls at once
Had a girl with all stats exception affection at lv.7
Had a girl with all stats exception affection at lv.6
Made over 5 million G in the same run
Used banned badge on 3 hot guys
Reached 500% customer satisfaction
Made over 1 million G in the same run
Used banned badge on 3 rough clients
Constructed everything in the same run
Reached 300% customer satisfaction
Maxed a construction