It comes down to a couple of basic things.
Either man made himself (evolution), or he was created by a creator.
If man evolved, then he has n creator and has no life after death. He has nothing but his own opinion to base his morals on. So, if I decided that eating people was ok, nobody could tell me I was wrong because there would be no absolute truth or absolute right or wrong. This is the ONLY religion that does not have a creator. It teaches that man made himself and is responsible to nobody. And because of that it also tells us when we die, we cease to exist and that nothing at all in the whole universe matters in time.
It is a religion that tells us we can do what we like so long as we have a big enough stick in our hand to get away with it.
The religion of Mother Nature is one of evolution. One where man's own ability to survive at a cellular level caused him to create himself. The one with no good or bad apart from man's own opinions.
Then one needs to ask which creator he was created by, and how we can be acceptable and righteous before this creator. Are we able to be acceptable to this creator 100% as we are? Has anything made us bad/evil/unrighteous towards him? Are we as good as our creator is?
If the Bible is the religion to follow, then it tells us that nobody can follow God and also follow other idols at the same time. We cannot follow God properly if we are also making money the most important thing in our life. Or tv, or friends, or anything else. If God is not the main focus of our life, we are worshiping whatever is our main focus.
If God says not to
The Bible tells of a perfect God creating man as a perfect being with the choice to either follow God's ways or to reject him and be separated from him. Man chose to sin and in doing so he separated himself from his creator because man was now in a sinful state and our perfect creator had to take the payment from us that that sin deserved. Death. The Bible tells us that good works do not pay for bad works. Good deeds cannot undo a single sin. The only payment that can be made for sin is death. Man knew that was true before he chose to sin the first time.
The Bible's Christianity is the only religion that teaches us that man cannot do anything or say anything that can save himself. ALL the other religions, buhhdists, muslims, mormons, roman catholics - every other religion - says that man can in some way earn merit for his own salvation. But the Bible also says that man can't do anything perfectly good now and so every one of our good works is also marred by sin and counts, as Isaiah the prophet said, as Filthy Rags before God.
So that is the important difference between all religions. The means by which man can have his bad deeds forgiven and properly dealt with.