What impact does Hamlet's soliloquy in act 4, scene 4 have on the audience?This question can relate to both the modern day audience and the Elizabethan audience.
This is an interesting soliloquy because while Hamlet does comment on some admiration of Fortinbras, he doesn't say anything new about himself or his situation. The majority of the soliloquy is more of Hamlet bemoaning his situation and his lack of action. The last line of the speech might make the audience see Hamlet's renewed sense of purpose, but he has spoken like this before and still not taken decisive action.
If you examine the speech more closely, here are a few specific details to note:
His opening remark, "How all occasions do inform against me, / and spur my dull revenge," is a pretty sad remark from Hamlet. He recognizes that all kinds of circumstances have gotten in the way of his revenge (ie. Polonius, his mother, Ophelia, his friends) and that his revenge is now dulled. He is on his way to England! He couldn't be further from Claudius and revenge!
He goes on to question his lack of action, again. He questions his purpose of earth asking if it is only to "sleep and feed," and then wonders why God gave man the ability to reason if it is only "to fust in us unused." He also comments, again, on what he understands to be his cowardly behavior. He even recognizes that his lack of action is "one part wisdom / and ever three parts coward." He knows that he has "cause, and will, and strength, and means / to do't," but that he hasn't yet and doesn't know how he ever will.
He sees that Fortinbras is a "delicate and tender prince / whose spirit with divine ambition puff'd / makes mouths at the invisible event," and that he risks lives of many men, even "for an eggshell" because it is what he wants to do and thinks he must do in the name of honor.
Ultimately, Hamlet is re-inspired to do what he needs to do for his very worthy cause. He ends the speech on a personal rally cry: "From this time forth / my thoughts be bloody or be nothing worth." It is a very forceful and energetic statement. Perhaps the audience is inspired in their continued support for the hero, but it is still left wondering how anything can happen if Hamlet gets on a boat to England where they already know Claudius plans to have him killed.