While all varieties of Buddhism revere "Buddha" and "buddhahood", they have different views on what these are. Whatever that may be, "Buddha" is still central to all forms of Buddhism.
The Dharma is the second of the three jewels which all Buddhists take refuge in. All Buddhas in all worlds, in the past, present and in the future, are believed by Buddhists to understand and teach the Dharma. Indeed, it is part of what makes them a Buddha that they do so.
Mahāyāna Buddhism also differs from Theravada and the other schools of early Buddhism in promoting several unique doctrines which are contained in Mahāyāna sutras and philosophical treatises.
These Indian Buddhist ideas, in various synthetic ways, form the basis of subsequent Mahāyāna philosophy in Tibetan Buddhism and East Asian Buddhism.
In different Buddhist traditions, other related practices which focus on fasting are followed.