Hannibal could have written his own book on war. He spanked the Romans black-and-blue every time they met on the field. Very likely, if Carthage had had a reliable naval supply line to him in Italy, he could have made the entire Roman federation break up and join him — that is what he was aiming for.
Instead, Rome's allies, knowing that he couldn't cover every place in Italy, and couldn't stay there forever, put two and two together and opted to try to keep Rome happy meanwhile.
Eventually a new generation of Roman leaders arose who had studied Hannibal's methods, and were able to use them against him.
And the one part he mentioned - about Hannibal funneling Rome's 'overwhelming' Legions into a small gap - reminded me of Thermopylae (480 BC) with King Leonidas and his 300 Spartans (1), against Xerxes and his 'overwhelming' Persian forces.
(1) Molon Labe