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