did he really die this way excecuted in the Senate,
Yes, stabbed to death by multiple people (supposedly 60+) in the Senate [Theatre of Pompey], but a different petition was introduced to Caesar, and some of Caesar's peers, who learned about the plot just before it occurred, had tried to protect Caesar. There are many historical accounts of those final moments with variant details.
Even though the play is entitled "Julius Caesar", it's focus is not Julius Caesar.
The play is about the thoughts, motivations, inner struggles, accountability issues, etc, of political peers precipitating, and proceeding, a political assassination, and the play also presents the complex nature of general citizenry (the citizens' political persuasions were inconstant as shifting sand).
Shakespeare wrote the play as a direct metaphor reflecting the political climate of his time.
Any political leader could have been the object of assassination.
Shakespeare took us inside the mind of assassins in order to show us the grave intellectual challenges politicians (and citizens concerned about politics) grappled with daily.
Were they striving to accomplish political goals for personal gratification/self-preservation, for the common good, for Democracy, for the preservation of their state [patriotism], for the preservation of everything their founders worked hard to forge [culture/civilization], etc? Is murdering a potentially dangerous leader a valid method of pre-emption, what is friendship, what is honour, are citizens flattering fickle flip-floppers for pledging unconditional allegiance to consecutive leaders with oppositional agendas (Pompey then Caesar...), or are citizens patriotic for unconditionally supporting whoever the current leader is as long as the leader is a fair ruler and represents the common good, etc?
Shakespeare poses these questions, and more, and there are obviously no clear answers.
The actors who portrayed Caesar and Anthony both resembled Brando.
I too thought Anthony's delivery at Caesar's funeral was fantastic. Each sentence was delivered as slowly as possible, with Anthony pausing between each sentence to allow the citizens to adsorb the impact of his words, and to allow him to gage their reaction (very important - his remarks were contingent upon their reaction because he was manipulating them to revolt against Brutus...) stheir reaction . His tone of voice shifted from naivety to lugubriousness to mockery to disbelief to ridicule to anger.
I've just watched the 1953 version. It is light years more impassioned and electrifying than this version (cinematography always helps...).
I'm not a fan of Marlon Brando (but that doesn't mean I don't like his films or performances), but I thought his delivery was brilliant. He provided one of the best performances of Marcus Antony that I have seen so far, equal to Charlton Heston and Patrick Stewart (stage) and Richard Burton. Brando should have participated in more Shakespeare films, he was a natural, he was more at ease and more captivating than his co-stars James Mason and John Gielgud.