The Vipassana meditator uses his concentration as a tool by which his awareness can chip away at the wall of illusion which cuts him off from the living light of reality. It is a gradual process of ever-increasing awareness of the inner workings of reality itself. It takes years, but one day the meditator chisels through that wall and tumbles into the presence of light. The transformation is complete. It's called liberation, and it's permanent.
Liberation is the goal of all buddhist systems of practice.
But the routes to attainment of the end are quite diverse. There are an enormous number of distinct sects within Buddhism. Mahayana Buddhism prevails throughout East Asia, shaping the cultures of China, Korea, Japan, Nepal, Tibet and Vietnam. The most widely known of the Mahayana systems is Zen, practiced mainly in Japan, Korea, Vietnam and the United States. The Theravada system of practice prevails in South and Southeast Asia in the countries of Sri Lanka, Thailand, Burma, Laos and Cambodia.