Are all religions worshipping the same God?
It is central to Christian belief that when anyone in the world, no matter what their circumstances or religion, cries out to God, he hears and responds. It is also true that three of the world’s major religions – Christianity, Judaism (Jews) and Islam (Muslims) – all worship the God whom Abraham worshipped approximately four thousand years ago. In that respect it is absolutely certain that no faithful adherent of any religion has put himself or herself beyond the reach of God.
However, Christians speak about God in ways that make their faith completely unique. The Bible speaks of God as Father, creator of all things. It also speaks of Jesus Christ, the historical figure who lived about two thousand years ago, as God. And it speaks of God as Spirit, active in humans and in the world – the Holy Spirit (known in past centuries as the Holy Ghost). When seen in this complete way, it is clear that not all religions worship that God.
Christians never talk of their three experiences of God as if they were three separate Gods. They always speak of one God. They worship a Trinity – God the Father, God the Son and God the Holy Spirit – one God with different characteristics. It is the very great reverence that Christians have for Jesus, not only following his teaching but submitting to him as God, that makes the difference between Christianity and other faiths most clear.
The question of how Christians relate to those of other religions is becoming increasingly pressing. Television and migration have swept away the ignorant assumptions of Christians in former times that those of other faiths were wicked or benighted. More and more evidently there is a willingness of good people of all religions to work together to address racism and poverty. However, it is undeniable that there are groups within all religions (including Christianity) whose extreme opposition to the cultures which have been shaped by other religions has led them to violence. Nothing whatever in mainstream Christian belief suggests that this is acceptable.
Dialogue between people of different faiths is at its best when it seeks understanding, rather than agreement. Jesus commanded his followers to love their neighbors in the same way that they love themselves. Most Christians seek to live positively with their neighbors while being true to the most important parts of their faith. But they also want to be open with others about their beliefs, sharing what they have found to be life-enhancing.

No they don't all worship the same God. They do not all worship Jesus Christ. Thus why it's called "Christ"ianity. Because we worship Jesus "Christ". We've always worshiped him since the beginning of time.

Dialogue between people of different faiths is at its best when it seeks understanding, rather than agreement. Jesus commanded his followers to love their neighbors in the same way that they love themselves.