Is Everything Allowed In The Christianity Religion Or There Is Things That Are Not Allowed?

I'll give you the simple answer to your question. But first, let me ask you a question. What was the first sin? If your answer is "disobedience", you are correct. God told Adam and Eve not to eat of one specific tree. But they did. They disobeyed God. Jesus Christ came along to offer us the way to set things right with God. That in no way means we are perfect. We will still disobey. Our way out is our repentance and His forgiveness. The final installment of God's plan will be Judgment Day. When we each receive our eternal reward/punishment, evil will cease to exist. Then disobedience will be a thing of the past. "things that are not allowed" will no longer be necessary. But until then, anything we do or say that is against His will is considered disobedience (sin).

As a once popular (later disgraced) comedian once said - there's a lot more do's than don'ts in the Bible, and if you spent your time doin' the do's, you wouldn't have time to do th don'ts, but if you did, you wouldn't, so you don't, so its cool.

Not everything is allowed in christianity. For example: Music, listening to the world music that does not talk about god. Like rock it does not have nothing to do with god

The Bible gives Christians a list of Morals to strive for. They are called the 10 Commandments.
                                 
                                10 Commandments
I am the Lord thy God, Thou shalt have no other gods before me.
Thou shalt not make unto thee any graven images.
Thou shalt not take the name of the Lord thy God in vain.
Remember the Sabbath day, to keep it holy.
Honor thy father and thy mother: That thy days may be long.
Thou shalt not kill.
Thou shalt not commit adultery. Thou shalt not steal.
Thou shalt not bear false witness against thy neighbor.
Thou shalt not covet thy neighbor's house.