These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Alternative Character Interpretation: Did Gilda really commit the first few murders or did Harvey's transformation into Two-Face cause her to snap and imagine she did? Likewise, did Alberto really commit all of the Holiday murders or did he just steal the identity after the first few murders and took credit for all of the murders? For that matter, it's hinted that Harvey might have committed some of the murders before he became Two-Face. There's also the question about whether of not Calendar Man really did know anything of the murders or if he was just using it as a grab for attention so he isn't forgotten.
Or, Alberto is a serial confessor (someone with a compulsion to confess to crimes), and that he only attempted the final murder, when he's captured by Gordon and Batman, and that all of the murders are commited by Harvey and Gilda, as suggested by the Calender Man.
Anti-Climax Boss: Done deliberately with Carmine Falcone. After having been an invincible crime lord for ages, he's casually shot dead by Two-Face. It perfectly highlights how the old school criminals and mobs are powerless against the truly insane and nigh-unstoppable supervillains that are taking over Gotham's underworld.