To Refute Christianity, One Only Needs to Look to the First Book of the Bible

I was once a Christian, until I found I could no longer delude myself when considering the tough questions of the Bible, and their "answers."  What are the tough questions?  They are the instances that defy logic and reason, demanding impossible explanations to validate their claims to truth.

For example, the New Testament describes a god that loves the world.  This god supposedly loves the world so much that he sent his only begotten son to be sacrificed most brutally, so that every person who believes in his sacrifice will receive eternal residence in Heaven, even those who are the most guilty of punishment and least deserving of forgiveness.  So long as one has faith in the sacrifice and identity of Christ, one will be forgiven for their sins and enter Heaven.

The problem with this theory of a loving god is that this same god is also purportedly the one from the Old Testament; a collection of stories which describes a god who kills countless innocent people, including children, for transgressions that to any sane and rational person would not warrant such a bloodthirsty response.  If God so loves the world, why did he wait so long to show it?  Why did he authorize so many massacres of human beings in the Old Testament?  Especially, why did he kill the entire population save for one family if he could have saved them by sending his son?  

There is no logical answer here, except that the god of the Old Testament is different than that of the New.  If such is the case, then Christianity dissolves instantly, because its foundation is that its god is the one who created the world in the book of Genesis.  Then we are simply left with a horrifyingly tedious and ill-tempered, bloodthirsty dictator of a god.

There are countless other unanswerable questions of the Bible which refute its claim of being true.  This is merely one.  One which demands an honest Christian to question his entire religion, and to pronounce it untrue.