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