Complex sentence: His most acclaimed works consist of a few triptych alterpieces, most outstanding the Garden of Earthly Delights, and the best of which make innovative use of oil paint and especially glazed finish.
Split into simpler sentences: His most acclaimed works consist of a few triptych alterpieces, the most outstanding of which is the Garden of Earthly Delights. His best surviving panels make innovative use of oil paint and especially glazed finish.