Simon's Quest has three endings, all of which are triggered by the amount of time you take to complete the game. It's been argued and debated as to which is the best ending, but it seems that the longer you play, the better the ending you get, which, needless to say, is odd. Having played the Japanese version, a contributor has sent screenshot proof of the endings' true order. They are:
Midday - Simon kneeling by Dracula's Grave
This ending, according to the Japanese version, is the "best" one available, earned for completing it in under eight game days. Simon triumphs over Dracula and stares down the headstone under which he rests. Exhausted, Simon kneels down.
Simon then exits the scene, leaving Dracula at rest. As the epilogue nears its end, events subtly hints that although you overcame Dracula, he will be back.
As the ending closes out, Dracula's hand reaches through the soil to further prove that theory.
Daytime - Simon kneeling by Dracula's grave
This ending, received for finishing the game after eight game days have passed, is second in the order according to the Japanese version. This ending notes that although Simon triumphed over the Count once again, he couldn't overcome his wounds.
It then notes that Transylvania might find hope elsewhere--in the form of a young man. Sounds like a lead-in to a direct sequel, but Konami chose not to go in that direction.
Nighttime by Dracula's grave
This is seemingly the best ending in terms of content even though though the Japanese version defines it as third in the order. You'll have to let fifteen game days pass before you defeat Dracula in order to receive it.
It notes here that you once again overcame Dracula and peace is restored--the usual happy ending. It's too bad that this is considered the "bad ending," even though you'd think such an outcome would be desirable.