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