IN GTA IV, if you choose the "Revenge" ending, then Niko must pick up Kate and take her to the wedding in the mission, "Mr. and Mrs. Bellic". If you choose the "Deal" ending, then she doesn't appear at the wedding. However, if you view the cutscene with a tool such as, OpenIV, you can see that she does appear the the "Deal" wedding, but she cannot be seen in game, as she is simply lowered beneath the map.
Interesting, no?
They have similar scenes don't they? It'd make sense, just to import all the characters to appear in both scenes.
They have quite different outcomes for each. In the "Revenge" version
Jimmy Pegorino drives up in a car and tries to shoot Niko, but ends up killing Kate. He drives off and Niko examines Kate's body and claims that it was his fault that she died and how he thought he got 'out' of crime.
In the "Deal" version
A man walks up behind Niko and says to him, "A gift from Dimitri Rascalov" and points a gun to Niko's back. Niko grabs the man's hand and tries to wrestle the gun out of his hand. Shots fire during this process and Niko manages to get the gun pointed to the assassin's head, where he manages to fire the gun at the assassin. Niko turns around to see Mallorie mourning over Roman's body as he was caught in the flurry of bullets shot by the assassin. Niko then shoots the body repeatedly and then goes ballistic on it, but Little Jacob stops him. He then tells himself about how Roman told him to get 'out' of it and he thought that he did.
Here's a video: The cutscenes are at 5:10 and 8:46.
I only did that one where Kate died. I found out Roman dies in the other one and just kind of assumed they were more or less the same. Still, same location and point in game.
Why take her out if she wasn't going to do anything important? This was clearly changed late in development as they didn't decide to rework the cutscene to not include her, but instead drop her down, out of view.