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