Power
Within Henry IV, Part I it seems that there are two main types of power. The first of these is emotional power: for example the type of emotional power that Hal holds over Falstaff who is dependent upon the Prince and in many ways needs his approval. The second in political power: that of kingship which the rebels challenge.
It is obvious that there are varied ways of obtaining either of these types of power. Hal manages to keep Falstaff slightly subservient through the fact that he will in time be king. He also mocks and jibes his friend, both inciting admiration through his quick wit and sharp tongue and leaving Falstaff seeking for his approval in certain sense. The ways of gaining political power are far more obvious - a leader can be deposed - just as Henry IV did Richard II. It can be gained through war, rebellion and violence - the rebels attempt this, although they do not succeed. Hal hopes to achieve such power through inheritance and no other effort whereas his friend Falstaff believes that he will get it simply through connection when Hal becomes King.
Where the power lies within the play is a slightly more complex issue. Certainly the rebels do hold power despite being disorganized, simply through their number and their impetuous will to achieve. Hal has an individual power - he controls himself and his fate. In this respect he has a power over those that surround him and depend on him. His father needs an appropriate and stable heir due to the dubious way in which he inherited the throne so is essentially at his son's mercy as are his wastrel friends who look forward to him becoming king and need him for their enjoyment. To a large extent Henry IV's power lies in his title and little else: it is only because he is King that so many people obey him. Therefore in a conventional sense he does hold supreme power over the country yet the rebels believe that they are entitled to this power as they helped the King succeed the throne. Their power over him lies in the fact that they represent a challenge to him.
It is hard to define who exactly holds the power within the play - what seems to be true is that the power shifts from the usurpation of Richard II's throne to the rebellion to the fact that Hal will inherit. Power is hugely manipulated: Hal misuses the power he has over his father in order to behave as a reprobate and over Falstaff to deceive and trick him. Falstaff hopes that Hal will misuse his power as King in order to pardon his friend's bad behaviour.
Role Play and Disguise
In many ways Hal seems to be playing out a role in his youthful foolishness that contrasts so strongly with the heroic elements in his character. This interplay between the stately and the personal becomes the central preoccupation of Shakespeare in the play's two sequels. Within him there is a great conflict between vice and virtue: his struggles with his awareness that he has political responsibilities and his lust for enjoyment and the high-life. He is a mix of the comic and the serious. At Eastcheap he does not behave like a Prince but instead employs smutty, colloquial language ("Why, what a pox have I to do with my hostess of the tavern?"). When he enters the court he becomes much more serious: he is aware that at some point "this loose behaviour I [must] throw off". At this point in the play he employs the use of verse rather than prose. It seems that the language he uses is also part of his disguise which is in certain ways calculated and two-faced but can hardly be termed hypocritical.
It is certainly questionable whether at the end of the play Hal has actually changed and become the honourable son his father wanted or whether he is still in conscious disguise to "glitter…attract more eyes". Certainly if this is the case it works with Vernon who, in Act IV, Scene I refers to him as "glittering in golden coats."
The use of disguise in Gadshill is a dramatic force and in a comical sense a source of tension. The comedy is built up as the audience know that Hal and Poins are in disguise whereas the characters do no. It is Shakespeare's private joke with his viewers it also helps to highlight specific facets of character's personalities (e.g. Falstaff's dramatic exaggeration).
Hal and Falstaff's role-play in the tavern is a point of high dramatic tension within the play - initially it seems to be just a game, however with Hal's final words of "I do, I will" we have to question whether actually is true and serious intentions are in fact being revealed. It can be seen as the climax of the powerful father / son dynamic which has existed between the fat old knight and Hal: from this point on Hal turns to his real father and rejects his misbehaviour of the past.
Disguise also plays a large part in the battle of the royalists over the rebels. With those loyal to the King such as Walter Blunt disguised as the ruler himself the rebels are confused and distracted. Not only can this disguise be seen as a sign of political victory but also it seems to highlight the futility of kingship. If it is so easily imitated and indeed picked up (as Hal proves) is it really worthy of all the stigma and respect that surrounds it?
When Falstaff pretends to be dead it is a very telling moment. Hal's true attitude towards his friend becomes apparent; "Death hath not struck so fat a deer today" thus he still makes a cruel joke at the expense of Falstaff's weight - we are asked to question whether the Prince used his friend for his own enjoyment.
Honour
Honour is one of the most enduring themes within the play and works on many levels with the various characters who have different perceptions of what 'honour' is:
HOTSPUR
He is described by the King in Act I, Scene I as "the theme of hounour's tongue" and by Douglas in Act IV, Scene I as "the king of honour". For Hotspur honour is really his ultimate goal, it is what he strives to achieve before anything else, even love, as he tells his wife in Act II, Scene III "When I am a horseback / I will swear I love thee infinitely". This clearly illustrates how his militarism dominates all aspects of his life and temperament. Hotspur's definition of honour is a military glory - being willing to risk your life on the battlefield in pursuit of individual glory. He has little sense of fighting for a general good or cause even though he claims to be involved in the rebellion to rid the nation of "this ingrate and canker'd Bolingbroke". His selfish goals are revealed in the dispute (Act III, Scene I) over the division of the kingdom - he demands a larger share, showing his irrationality when he demands:
"I shall not wind with such deep indent
To rob me of so rich a bottom here"
This shows Hotspur's need to have material validation of his military goals. In the pursuit of honour he is completely selfish and driven by a need for personal fulfillment.
Hotspur also adheres to the view, perpetuated by the political figures of the play, that achieving honour on the battle field makes you a superior being, for example he condemns Hal in Act I, Scene III as "that sword and buckler Prince of Wales". This implies that Hal is incompetent on the battlefield by depicting him using very basic armour and he uses this as a basis for his claim that "I think his father loves him not". Hotspur is very arrogant and thinks that his military glories give him more importance than the Prince of Wales. For him honour is the defining point of his identity therefore it is fitting that he does die an honourable death on the battlefield despite the fact that ironically it is at the hands of the Prince he has so mercilessly scorned. With the loss of his honour to Hal he also loses his will to live:
"I better brook the loss of brittle life
Than those proud titles thou hast won of me"
Despite his valiant attempts Hotspur is not essentially an honourable character. He lacks loyalty and compassion, he has too narrow a perspective on life and is totally self-focused and greedy.
HAL
Hal's concept of honour is ambiguous because although by the end he appears to adhere a military view of honour, initially he mocks and parodies it. In the beginning Hal's lack of honour is a defining point of his character - it is the only indication that he will come to hold his future position comes in his soliloquy at the end of Act I, Scene II:
"And like bright metal on a sullen ground
My reformation, glittering o'er by fault"
Hal cannot even be seen to possess honour in relation to his loyalty towards his supposed friends such as Falstaff at Gadshill. Nonetheless as the play progresses and certainly by the time the King and Hal are reconciled in Act III, Scene II, Hal has accepted the traditional view of honour. He calls Hotspur "child and honour" and says:
"I shall make this northern youth exchange
His glorious deeds for my indignities."
By the end Hal has gained his honour through his military success: he has slain Percy (Hotpur) and saved the life of the King. In Act V, Scene IV his father says "Thou has redeemed thy lost Opinion". We might question the state of honour towards his friends, however.
FALSTAFF
His concept of honour is the antithesis of the accepted and traditional view - it can even be argued that in this world of overblown military valour he serves as the voice of reason. Initially he appears as a wholly dishonourable character - he lives a life of debauchery and theft which he calls "my vocation" in order to excuse his behaviour. His exploitation of his charge of foot in order to generate personal profit by allowing his wealthy officers "toasts and butters" to buy out their service and employing the poorest most ill-equipped soldiers to fight (all 350 of who die) only exacerbate this view.
Nonetheless it becomes apparent that Falstaff has a unique perception of honour i.e. it is more useful and worthwhile to focus on preserving your life and avoiding the horrors of war, than actively seeking death.
In Act V, Scene I Falstaff says "What is honour? A word….What is that honour? Air….who hath it? He that died - a - Wednesday." Falstaff sees the futility and emptiness of this ideal, he values tangible concepts such as his own morality as shown in Act V, Scene IV where he states that "The better part of valour is discretion". This echoes the view of the Elizabethan public whose contempt for such outdated concepts was widespread.
OTHERS
The King, his nobles and the rebels all pursue the chivalric ideal of honour. But this is in a way tainted by the connection they all have with Henry IV's shady succession to the throne: so can they really be considered as honourable?