The Player is the leader of the Tragedians. He is "just" an actor, but he seems to be more in control of reality than almost anyone else around. In his view, life itself isn't too different from being an actor in a play, and he doesn't understand why someone like Guil is always questioning everything rather than just playing his part. He tells him to "Relax. Respond. That's what people do. You can't go through life questioning your situation at every turn" (2.150). He claims to have been more of a purist back in the day, but now he and the Tragedians more or less do whatever they are paid to do. He offers to put on a smutty performance for Guil and Ros, and later agrees to perform The Murder of Gonzago with Hamlet's altered lines.
The Player is pretty good at spouting off fancy poetic lines the same way that Guil does ("We ransomed our dignity to the clouds, and the uncomprehending birds listened") (2.114). The difference is that he is not nearly as bothered by the philosophical questions as Guil is. For him, it's all just child's play, and the result is that he is immensely confident while Guil is insecure. Yet there are certain consequences of viewing all of life as just one big play. We'll get into these below.
The Player can be pretty cheerful and friendly, but he can also turn on you like a rabid dog. There's something very threatening underlying his whole demeanor. It's subtle, but it's there. The first example is when he strikes Alfred without explanation. He also tries to cheat Ros and Guil and, in the closing scene, as Guil and Ros's fate approaches, the Player's debonair sense of cool becomes truly menacing.
This menace is inter-woven into his argument about death with Guil. Consider the story that the Player tells about the actor in his troupe that was condemned to death. He manages to get permission for him to be killed during one of their plays. Now just think for a second how incredibly twisted that is. He attempts to turn an ordinary man's death into public entertainment. And does he have any remorse about it? No. He says:
The whole thing was a disaster! – he did nothing but cry all the time – right out of character – just stood there and cried […] Audiences know what to expect, and that is all they are prepared to believe in. (2.339)
This is one of the consequences of viewing all of life as a play. Nothing is quite real to the Player, and as a result his morals are quite perverse.
The thing about the Player is that he sees no distinction between life and art. He has essentially traded in his life to become a permanent actor. Guil wants art to imitate life the same way the Player does, but for him life and art are separate. For the Player, though, nothing is sacred – he thinks that a play can do anything. It is all just about acting appropriately, playing your role, and managing the expectations of your audience. This idea reaches its peak when he fakes his own death at the end of the play, and does it so well that he fools both Ros and Guil. The Player "wins" the argument about whether death can be believably portrayed in art, but he is also out of touch with reality – a heavy price to pay.
The Player does have one big weakness. And we mean big. When Ros and Guil abandon him in the first act of the play, all of his confidence comes crashing down. The next time he sees them, he has a temper tantrum. He says: You don't understand the humiliation of it – to be tricked out of the single assumption which makes our existence viable – that somebody is watching. … The plot was two corpses gone before we caught sight of ourselves, stripped naked in the middle of nowhere and pouring ourselves down a bottomless well. (2.112)
At first it's almost hard to understand why he's so upset. He's like a child that has been abandoned by his parents, and when he finds them again he is furious.
An audience provides the one level of assurance that the Player needs to maintain his view of life. He acts all the time, and he's OK viewing life as one big play, but this means that he needs people to watch. He needs them to watch constantly or else there's no point in acting. The Player believes in an audience the way that many people believe in God. Without an audience, his life just doesn't make sense.
Let's zoom out for a moment here. The Player is an actor in the context of the play, but he's also a real person (Jules Roach in the original production), and we're the people sitting in the theater making his role worthwhile. We are involved in the action of the play. We are part and parcel of Rosencrantz and Guildenstern are Dead. Imagine Stoppard's play being acted out without an audience, and you can very quickly see why the Player is so upset.