The God of the Roman Catholic Church and the God of the Protestants is one and the same. The major difference is in the way that they interpret interaction with God. Both rely on the Old and New Testaments as the foundation of their faith; although each interprets the teachings of Jesus (whom both consider to be the Son of God) differently. There are many similarities in the rituals of the Catholic Church and some Protestant Churches, although there is more variance in ritual than anything else. The Catholic Church teaches that salvation, although a gift from God, is the result of faith and good works. Protestant churches by and large teach that salvation is also a gift of god, but comes from faith alone. It should be remembered that Protestantism itself developed as an offshoot of the Catholic Church; those who "protested" Church doctrine were known as Protestants.
The Protestant and Catholic church both worship the same God the difference is in their method of practiced worship. The Catholic church has stricter rituals and focuses more on rules, do's and don'ts, and the practice of good works. Whereas christianity is more lenient but not to be confused with not taking it seriously. Christians are taught more about the free gift of salvation that relies more on the faith.