Moe Green (Dramatic Irony)
Hyman Roth recounts how he asked no details about the murder of his close associate Moe Green to signal to Michael that good mobsters don't ask questions about major decisions, but rather let sleeping dogs lie. The dramatic irony here is built because it is somewhat ambiguous if Roth is aware that Michael ordered the hit on Moe Green, but it is clear that Roth's hit on Michael is karmic in one way or another. In this sense, the irony is constructed like that in Greek tragedy, where some forgotten transgression leads to the total ruin of our hero later rather than sooner.
A Shooting During the Festa (Situational Irony)
One of the most delicious pieces of irony in the film comes during one of its most iconic scenes, when Vito shoots Don Fanucci as fireworks are going off at the festa. On one hand, it's ironic that Don Fanucci is being murdered at the exact moment when the whole neighborhood is celebrating a martyred saint but, on the other, it registers as a perverse celebration for Vito's victory over an insidious, extorting capo and the first step on his own rise as something of a compassionate mob boss.
Michael's Take on the Miscarriage (Dramatic Irony)
When Kay goes to leave Michael, he starts bargaining with her, saying he knows that she blames him for the miscarriage. The implication here is that Michael thinks the miscarriage was a result of the attempt on his life. He quickly learns that Kay had the baby aborted, and he flies into a fit of rage. Through this, we learn so much about Michael's self-centeredness, the broader irony that he constantly thinks he is being strong for his family and doing what's best by them, when he's really just out on a series of ego trips. After all, when he learns of the miscarriage earlier in the film, he doesn't ask Tom if Kay and the kids are alright, but if the baby lost was a boy.
"I'll make him an offer he can't refuse" (Situational Irony)
We first hear Vito say this line in the first Godfather movie in reference to having a conversation with a film executive. We witness the young Vito say it in this movie too, in reference to haggling with Don Fanucci over an amount of money that Vito and his friends are being extorted for. But it's not verbal irony in this film as it was the last—the implication isn't that Vito is going to threaten Fanucci's life — but rather situational, in the sense that Fanucci actually does not refuse the offer. He gladly accepts the smaller amount of money and praises Vito for having the balls to pull such a stunt. In fact, on his way out, Fanucci is offering Vito a chance to be taken under his wing. The real irony is that Fanucci doesn't realize he shouldn't turn his back when Vito is around.
