Spoilers ahead, read at your own risk!There are several different endings for Dreaming Mary. The names for the endings listed here are not official.
Ending 1 (True Ending) Edit
Conditions: Obtain all red seeds and lose all of your petals, then enter the door (with the four holes).
Result: Mary goes deeper into her dream.
Ending 2 (True Ending Alternate) Edit
Conditions: Obtain all red seeds and have at least three petals before Boaris takes one, then enter the door (with the four holes).
Result: Mary goes deeper into her dream. This time, hands (presumably Mari's father's) appear in the doorway.
The end credits are also slightly altered, and say "The beginning of a nightmare" after saying "The end of a dream" as it does in the first true ending.
Ending 3 (Nightmare Ending 1) Edit
Conditions: Find the nightmare world and get caught by the shadow.
Result: Mary/Mari is shown with her hands covering her mouth. Bunnilda, Penn Guindel, and Foxanne are shown hanged. A shadowy figure of a man looms overhead, presumably Mari's father.
This ending does not have a credit roll and brings you back to the title screen without the option to restart on the same file. Thus, it is more like a "game over" than an actual ending.
Ending 4 (Nightmare Ending 2) Edit
Conditions: Find the nightmare world and escape the two rooms, but do not have all the rusty keys.
Result: Mary cannot escape the dream and the shadow catches her.
An alternate end credit plays, playing "Elegy for the Dream" instead of the regular credits theme. This credit roll does not show any of the characters and the background and text is purely black with red, blood-like splotches and smears.
Ending 5 (Nightmare Ending 3) Edit
Conditions: Escape the shadow and have all the rusty keys.
Result: Mary awakes from her dream, but cannot leave her room and is forced to stay awake or go back to sleep.
This credit roll is the same alternate version as in the ending above.
Ending 6 (Good Ending) Edit
Conditions: Same as above, but ensure that you have the Gold Leaf Key.
Result: Mary awakes from her dream and escapes the mansion and her father.
Ending 7 (Joke Ending) Edit
Conditions: For the fish bowl password, type in "SUPERMARY". Return to the nightmare world and approach the dark figure.
Result: The player gets a joke ending.