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