Was C.S. Lewis a Christian?

I came across this video today, and it sums up, very briefly at that, a few conversations that I have been having recently. Was C.S. Lewis a Christian? My contention is that he was not, to be even briefer than this video was, he believed in purgatory (The Great Divorce is his statement on this topic), evolution (see Mere Christianity), never repented of sin and turned to Christ as a clear understanding of salvation (see Surprised by Joy, which is his "salvation testimony.")

If one would like to do more study, please, watch this video first, then go here for starters. Please, do not misunderstand, Lewis was a great writer, but that does not mean that he understood true Biblical Christianity.  He simply, in his own words, became a "Theist." But just believing in God is not enough - James 2:10, John 8:30-59, Matthew 7:13-23.