The fundamental distinction between Christianity and other religions arises from the fact that in Scripture the initiative in religion is not taken by human beings but by God.
In pagan religions it is human beings who seek God (Acts 17:27). In every way they attempt to bring God down to themselves and into the dust (Romans 1:23), and by all kinds of methods they try to achieve power over God.
But in Scripture it is always God who seeks human beings. He creates them in His image and calls them after the fall. He saves Noah, chooses Abraham, gives His laws to Israel. He calls and equips the prophets. He sends His Son and sets apart the apostles. He will one day judge the living and the dead.
The religions of the nations, on the other hand, teach us to know human beings in their restlessness, misery, and discontent but also in their noble aspirations and their everlasting needs – human beings both in poverty and riches, their weakness and strength. The noblest fruit of these religions produces humanism. But Holy Scripture teaches us to know God in His coming to and search for human beings, in His compassion and grace, in His justice and His love.
(Taken from Reformed Dogmatics, Volume 1: Prolegomena, p. 327-328)
The thing that sets Christianity apart is the God it worships: the God who comes, seeks, and finds. This is why the symbol of Christianity is not a ladder for man to come to God, but a cross where God came for Man.