Here is the full list of all 35 Disc Room achievements.
UNCOVER THE GOLDEN MYSTERY
EXPLORE ALL ???? ROOMS
COMPLETE HARD MODE
SURVIVE 10 SECONDS IN EVERY HARD ROOM
EXPLORE ALL HARD ROOMS
SURVIVE 20 SECONDS IN ANY HARD ROOM
START HARD MODE
DEFEAT THE ULTIMATE GATEKEEPER USING EVERY ABILITY
SURVIVE 20 SECONDS IN EVERY ROOM
EXPLORE ALL ROOMS
DIE FROM ALL DISCS
FOLLOW THE PATH
DISCOVER THE FOURTH GOLDEN ROOM
DEFEAT THE ULTIMATE GATEKEEPER
???? THE ????
END A RUN FROM THE MAP
UNLOCK ALL 6 ABILITIES
WALK 10K STEPS
DISCOVER THE THIRD GOLDEN ROOM
QUIT TO MAIN MENU WITHIN 2 SECONDS AFTER DYING
DEFEAT THE PHANTOM GATEKEEPER
SURVIVE 20 SECONDS IN EVERY ROOM IN ONE ZONE
HOLD DOWN FFW FOR 10 SECONDS STRAIGHT
FACE THE GOLDEN CARCASS
DEFEAT AND REVIVE AN ANTIBODY
DEFEAT THE CARNIVOROUS GATEKEEPER
DISCOVER THE SECOND GOLDEN ROOM
SURVIVE 60 SECONDS IN ANY ROOM
FEED ???? 4 ????
DIE FROM 4 DIFFERENT DISCS IN ONE LIFE
DISCOVER THE FIRST GOLDEN ROOM
DEFEAT THE OVERGROWN GATEKEEPER
DIE FROM ALL DISCS IN ONE ZONE
SURVIVE 0 SECONDS OR LESS
DEFEAT THE ARMORED GATEKEEPER