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