Christianity is a salvation religion because it teaches a message of salvation which is supposed to apply to all of humanity.Whatever the exact circumstances, though, the long-term purpose of life is generally treated as reaching salvation and God.
Christianity is also a revealed religion because it traditionally focuses heavily upon revelations from God. For most Christians, the entirety of those revelations can be found in the Bible, but some Christian groups have included revelations from other sources as well. It's not important where those revelations happen to be collected; what is important is the idea that they are a sign of an active god who is very much interested in what we do and how we do it. This is not a Watchmaker God who is simply observing us, but instead one who has taken an interest in human affairs and intends to direct us on a path deemed appropriate.