Due to the very... weird nature of this game, there's lots of this to go around in The Binding of Isaac.
- Is Isaac a victim, a sacrifice, the spawn of the devil (possibly even the Antichrist), or Messianic Archetype?
- Is ??? Isaac post-suicide? Is he his own person?
- Are the other playable characters alternate personalities? If not, are they related to Isaac? Is ??? one of them?
- Is Mom a religious zealot, just insane, or both? Did she go insane from religion, raising Isaac, or her husband leaving them? This gets even more confusing with it being heavily implied she didn't really try to kill Isaac
- Is God evil or good in this game? Did He have Mom sacrifice Isaac for fun, as a test, or because he was the Anti Christ? Did He even ask her to do it or was she just imagining things? What is His relation to the Angels? The final ending seemingly confirms that God was on Isaac's side the whole time.
- Is Satan trying to protect Isaac or awaken him as the Anti Christ? Does he just see Isaac as a customer and tries to get more payment in the Sheol path? How is he related to Mega Satan? Then there's the signs that he may even represent Isaac's Dad in some way.
- Is the Lamb supposed to be a demonic Jesus? A representation of whatever Mom "should" have sacrificed? Some other, skeletal, horned version of Isaac himself? Or just some other demon monster? Its general placement as the boss of a location accessed after Sheol is beaten and Satan himself is killed raise a lot of questions, especially seeing as it is the "negative counterpart" to ???.
- Did Isaac's Dad leave because he was a Jerkass, didn't feel like he could be a good family man, or to get away from his mentally unstable wife, who may have had several miscarriages?
- Repentance answered some of these questions. It turned out he was an alcoholic (and possibly had worse addictions, since he spent all of his family's savings), and his wife becoming more and more unstable only made things worse for him. His reason for leaving the family was, quoted, "I'm doing more harm than good."
- Is the ending where Isaac turns into a demon good or bad? Is Isaac finally happy?
- While the final ending provides some answers, it does raise its own questions. To what extent did Mom abuse Isaac, if at all? While her trying to kill him is a hallucination, the abuse implications in many items is hard to ignore. Why did Isaac's parents split and whose fault is it truly?
- In Repentance, one of the endings very strongly implies there was at least some abuse, as she ends up locking him in a closet after seeing a drawing he made depicting her as a monster. The way he reacts makes it sound very much like this was not the first time she'd done this to him.
- On the topic of the final ending, what is Isaac's ultimate fate? Ed says that he died, but he also left it ambiguous so it's not a clear cut answer.
What ultimately happens to Isaac? Is he staying dead, but finally realized he wasn't to blame for anything? Is he in Heaven telling stories with his dad, with this being his ideal afterlife? Is Isaac getting another chance at living, and he's at home telling bedtime stories?
