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