What makes the scene of Caesar’s assassination highly dramatic in Julius Caesar?

I love this question.  You are really investigating the
action of the play that accompanies the text
-- an investigation that is crucial to fully appreciating a work written to be performed
by actors rather than simply read.

This scene, which
happens in Act III, scene i, is dramatic on a couple of levels.  First, I would say that
much of the drama comes from the violent act happening onstage.  Shakespeare's audience
loved blood and gore just as much as the audiences of today do (or from any time), and
Shakespeare was all about creating entertaining spectacle for his audiences.  And not
only is it a murder enacted onstage, but it is a murder in which no less than seven men
attack and stab Caesar.  Gruesome!

The scene is also very
dramatic because Shakespeare really limits the lines that are spoken, leaving the actors
(and director) to create a scene of physical interaction that keeps the focus on what
the actors are doing, not what they are saying.  The only lines that are directly
related to the murder are the one that begins it and the one that ends
it:

readability="12">

Casca

Speak,
hands, for me!

[Casca first, then the other
Conspirators, ending with Marcus Brutus, stab
Caesar]

Caesar

Et
tu, Brute?  Then fall,
Caesar.

When I go into
classrooms to share some of the theatrical aspects of working with Shakespeare with
English students, I often have them stage this scene.  What's most interesting is having
them slow down and take the time to really think about what specifically happens, and in
what order.  It also provides them an opportunity to consider how suspense is created
onstage.

Some of the questions a reader might ask himself
about this scene are:

• Does one of the
  Conspirators wait to act until a certain other one (say Brutus or Cassius) does?
  


• Does one of the Conspirators try to chicken out and
  leave?


• How many times does each Conspirator stab Caesar
  (He is reported to have been stabbed 23 times by 7 men.)?
  


• Do any of the Conspirators have to be pulled off of
  Caesar because they have given way to a murdering frenzy?
  

These sorts of questions don't have one right
or wrong answer, but give someone who is simply reading the play a real sense of how
much of the action (even the action of a crucial event like the murder of Caesar) is
determined by those who will perform it.  The action of this scene is rendered,
potentially, even more dramatic than some, because Shakespeare really limits the words
that are spoken, allowing the actors and the audience to focus on what the characters
are doing.