Castlevania 64 Keys

Castle Wall: After dropping down from the right tower, it rests in a candle on the second floor

Opens the left tower near the stage's entrance

The Villa: Found in a vase on the second floor of the Villa mansion's first large room

Opens the far-north door of the Villa mansion's second floor

The Villa: Found in a vase in the Villa's ghost-haunted living room on the second floor

Opens the door immediately left of the Oldrey bedroom

The Villa: Given to you by Mary Oldrey after you bring her son to safety

Opens a locked door in the Villa hedge maze that leads to the stage's exit

Castle Center: Given to you by the mutated lizard man on the stage's fourth floor

Opens the door the mandragora room on the stage's bottom floor

Tower of Science: Found in a candle in a room guarded by turrets

Opens the double doors that leads to the surrounding halls

Tower of Science: Found in a small room room (in a set of three), guarded by a single turret

Opens the way to the stage's machinery room

Tower of Science: Found in the machinery room by working past a deadly production system

Opens the door the leads to the stage's exit route

Tower of Execution: Found in a sarcophagus on a hidden ledge on the stage's third floor

Opens a locked grating that leads to some power-ups

Clock Tower: Found in the stage's very first room, in a candle hidden near some gears

Opens the locked door in that
same room

Clock Tower: Second room, guarded by a pillar of bones in a small indent right of the locked door

Opens the locked door in that
same room

Clock Tower: Found innocently at the bottom of the stage's third room

Opens the locked door high above in that same room