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