Before this, Disney had never touched modern-day New York City as the setting of an entire animated feature. (The beginning and end of The Rescuers take place there, but most of the film is set in Louisiana.) Not only did they pull it off, but then the second musical number "Why Should I Worry" starts up, and the audience realizes this is going to rock.
Upon first meeting Sykes, his dogs, Roscoe and DeSoto, go into the gang's hideout and starts terrorizing the place. DeSoto finds Oliver's hiding spot, and ignores Roscoe telling him that Sykes is calling them back, in favor of preparing to eat Oliver. Oliver responds by clawing DeSoto's nose in self-defense, leaving scars. Even Fagin says that that took a lot of guts. This is based on the behavior of real-life cats, who are known to fight back when cornered.
After the clawing mentioned above, the two pinchers, naturally, get angry and are about to kill Oliver when the rest of the gang suddenly leaps to his rescue! And this is the same gang that hated him just minutes before! Also doubles as a Crowning Moment of Heartwarming.
Fagin coming to save Jenny and his pets, on his scooter. When you saw all through the movie how scared he was of Sykes, this definitely proves how brave he can be. Hell, the sheer fact Fagin endured a climactic chase sequence through a subway driving a scooter.
Seeing Jenny in danger, Oliver jumps onto Sykes' limo during a frenzied car chase through the subway system and bites Sykes on the hand. An audible hiss can be heard just before the bite.
Upon seeing Sykes throw Oliver into the back of the limo-with Roscoe and DeSoto-Dodger jumps across to the car and into the back to help Oliver out.
Dodger gets pinned by DeSoto over the back of the car after Roscoe slips onto the train tracks (failing a Taking You with Me attempt and getting electrocuted to death), but Oliver jumps onto DeSoto's head with his claws out, causing the Doberman to fall over the back too. Oliver almost gets launched onto the tracks as well but Dodger catches him by the collar. Just to recap that; by backing each other up, Dodger and Oliver took out both of Syke's dogs. Then they double-team Sykes himself to give Jenny time to jump to Fagin's scooter.
For Tito, driving the scooter off the railway just before they hit the train. The way he does it is pretty funny too.
Fagin, upon seeing Jenny sad and worried about Oliver, willingly gives him back to her (after pretending to mysteriously find him abandoned in a crate) despite the fact that he knows that Sykes will kill him if he couldn't get the ransom money.
Dodger and his gang ultimately redeem themselves for their friend Oliver by helping him and Fagin rescue Jenny from Sykes.
Bonus points for Georgette helping as well. She wasn't all showy about it either, the just huddles up with the other dogs with a determined look on her face and runs off to Sykes' hideout. This shows how much she really cares about Jenny.
Bonus points also for Dodger, who had earlier all but called Oliver a sell-out for wanting to stay with Jenny, being the one to declare that they'll save her.
Fagin pulling a Big Damn Heroes moment and charging into Sykes' hideout to drive out Jenny and the dogs. Again, Fagin is terrified of Sykes and his dobermans.
It's a small moment, but after Rosco and DeSoto fight and wound Dodger on Sykes' command, Fagin, who had spent the entire film terrified of Sykes, kneels down to comfort Dodger and gives Sykes a Death Glare.
Dodger jumping in to defend Fagin from Roscoe and DeSoto. If you look closely you can see Dodger actually overpowering DeSoto despite the latter being much bigger and more vicious than him. He only loses the fight because Roscoe jumped into the fray.
Despite being pretty brutally mauled by the two dobermans, Dodger seems pretty nonchalant about it when Rita shows worry.
Francis: (to Roscoe) Isn't it rather dangerous to use one's entire vocabulary in a single sentence?
Tito: Aha! Frankie, you did right! (gives him a high paw) You bad, boy!