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