Other religions also teach the existence of God. Is there any difference between their teaching and the Islamic concept of God?
The first major difference is that Islam teaches the absolute one-ness of God, with Whom no one can share in Divinity. No idol or heavenly object, nor any religious or spiritual teacher, can possess some Divine power or attribute.
Secondly, Islam teaches the highest conception of God, and does not accept any limitation to His power and knowledge, while other religions set limits to Him. For instance, Islam rejects the Hindu belief that God is not the Creator of matter and souls but exists alongside them. It also rejects the Christian doctrine that God is unable to forgive sins unless He punishes someone, and so He sent His 'son' to suffer the punishment for the sins of all humanity. Moreover, a son is needed to take the place of the father when the father dies, and clearly this cannot apply if God is perfect.
Thirdly, Islam refutes the idea that any human being, however great, was a 'manifestation' of God on earth, or a Divine incarnate.