Edmund McMillen's slightly disturbing indie dungeon crawler Binding of Isaac has been extended and expanded on this, the most spookiest of days. Don't expect any seasonal additions, however: In lieu of Jack O' Lanterns and mutant candy corn monsters, the free update features new bosses, a new playable character, an additional ending and a fifth chapter, which, in a fittingly bizarre twist, is "unlocked after 10 mom kills." Check out all the new features after the jump.

The game will be updated on Steam by 3 p.m. ET today. It's probably not the scariest thing you could play today, though. If only it were as utterly horrifying as its launch trailer!

BIG HALLOWEEN UPDATE (with no actual lame halloween themes)
  • Added chapter 5 (unlocked after 10 mom kills)
  • Added 3+ new bosses
  • Added 4 new enemies
  • Added 20+ new items
  • Added one new unlockable character (Eve)
  • Added one new "FINAL" ending.
  • Added 6+ new achievements
  • Added 2 new music tracks by Danny B
  • Added updated collection viewer
  • Added 4 new tarot cards ( finishing the major arcana )

This article was originally published on Joystiq.