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