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