What is unique about Christianity? Inspired by this question: How do Christians explain commonalities between their religion, other major faiths and obscure isolated tribal belief systems?

What is fundamentally unique about Christianity?  Obviously there are different stories, texts, and traditions associated with Christianity than with other religions.  But if we cut away all the fluff from all the world religions...  Is there anything that stands out as unique about the core of Christianity?



To clarify what I'm asking:


Many religions have prophets that claim to speak on behalf of god(s).
Many religions have scriptures, often claimed to be inspired by their god(s).
Many religions report miracles, or other supernatural phenomena.
Many religions claim to be the only "true" religion.
Many religions claim to offer forgiveness of sin.
Many religions claim to be historically based and accurate.
Many religions claim to improve society.


If Christianity just has a "better version" of all of these points, it sounds like Christianity is fundamentally the same as most/all other religions, it's just "more completely evolved."  So what I'm asking for is any characteristics of Christianity that are fundamentally unique and important, and not just improvements on existing ideas.
Many religions are attempts to please a god or "gods" in order to gain their favor.
Many religions focus on becoming more like a god ourselves, elevating man in some way or another 
Others deny God or the Supernatural at all (often viewing man as already being the ultimate being)
Many focus on using or harnessing powers of the universe to improve our lives (Wicca, and other new-age religions)


The primary difference between Christianity and other religions that I've either "dabbled in" or studied is this:

Christianity is unique in stating that we cannot possibly hope to please God by being "good enough", and that God reached down and made the ultimate sacrifice for us.  Our good works can do nothing to please Him.  All we can do to please Him is to accept His gift and love Him.

In other words, all of the other religions that I'm aware of are man-centered, focusing on improving or glorifying man, whereas Christianity is about glorifying God alone.  Instead of trying to appease Him in some way or other, which encourages pride, we are grateful to a God that loves us in spite of our own unrighteousness.  Christianity gives all the glory to God, and leaves no room for us to take any credit on our own.