Let me ask it this way, then: Does Christianity portend to worship the God of the Old Testament?
Not the same interpretation of the Old Testament for sure, not the same revelation of God - else there would be no need for the New Testament. Both Christian and Jew await the (return of) messiah, but for Christians Jesus Christ is the Messiah, true God from true God. This is true revelation for Christians, but blasphemy for Jews reading the Old Testament, as we see most dramatically in the events as told in St. John's Gospel.