I noticed some wierd things when i recently watched part II'
I believe when roberto comes in to see the young Vito to apologize Vito calls him DON Roberto. Why is this?

Also during the riot in miami if u look at the bottom of the screen during one of the shots there is a big black blob that is not part of the actual shot but a weird defect of the film(its the shot when the rioters knock something over right before people are smacking the parking meters)

Don is not just a mafia word. It is a title of respect.

Sr. Roberto calls Vito "Don Vito", out of respect. Vito shows he is a man who treats others with respect, so he calls Roberto "Don". Just what Freddie says.

The riots you're talking about take place in Havana, not Miami. I've never noticed the big black blob.

i,ve never noticed that either

The black blob might be something laying in the shadow.The riot scene was a pretty darkly filmed scene. Vito calling Roberto Don also shows Vito is humble.

I think it shows Vito being clever in an almost sarcastic way. The last time we saw Sr. Roberto before that scene, he was threatening to kick Vito's "Sicilian ass out in the street." Now, having learned about Vito, he calls him "Don Vito." And Vito, almost smirking, acknowledges this obvious attempt at flattery by replying "Don Roberto." It's one of many really neat touches.