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!