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