The Halloween Update was released on November 1st 2011 after the original Halloween launch was delayed overnight. It is a major update, and includes a massive amount of new content.

Update Notes:

• Added chapter 5 - Sheol (unlocked after 10 mom kills or through Demon room in Womb 2)
• Added 3+ new bosses including Satan
• Added 4 new enemies
• Added 20+ new items
• Added new unlockable character - Eve
• Added one new “FINAL” ending.
• Added 6+ new achievements
• Added 2 new music tracks
• Added updated collection viewer
• Added 4 new tarot cards (finishing the major arcana)

http://edmundmcmillen.blogspot.com/2011/10/binding-of-isaac-halloween-update.html

TriviaEdit

• There was originally just going to be the Pumkin Mask as an update but Edmund and Florian thought that was kind of lame so they made a big update with many additions instead and removed the holiday item. [1]
• According to Edmund an update of this size was also made to make up for the shaky Launch of The Binding of Isaac. [2]

VideoEdit

The Binding of Isaac Halloween Update(00:55)
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