The game includes three different endings, determined by how long it took for the player to complete the game and how many continues were used. All three are variations of the same ending, but with different twists featured.

Bad ending
Method: Complete the game in 15 days or more.

Neither Dracula nor Simon survive the battle. Dracula's grave is shown and text appears telling the player that:

"The battle has consummated. Now peace and serenity have been restored to Transylvania and the people are free of Dracula's curse forever. And you, Simon Belmont, will always be remembered for your bravery and courage."
— Bad ending

Normal ending
Method: Complete the game in 8 to 14 days.

Simon defeats Dracula but eventually succumbs to the curse anyway. Simon kneels by Dracula's grave and text appears telling the player that:

"Although the confrontation between Simon and Dracula has concluded, Simon couldn't survive his fatal wounds. Transylvania's only hope is a young man who will triumph over evil and rid the city of Dracula's deadly curse."
— Normal ending

Good ending (canonical) 
Method: Complete the game in 7 days or less.

Simon defeats Dracula and is freed from the curse. He kneels by Dracula's grave and text appears telling the player that:

"The encounter with Dracula is terminated. Simon Belmont has put an end to the eternal darkness in Transylvania. His blood and sweat have penetrated the earth and will induce magic and happiness for those who walk on this land."
— Good ending