The process in which a relatively unspecialized cell acquires specialized features of an amacrine cell, an interneuron generated in the inner nuclear layer (INL) of the vertebrate retina. Amacrine cells integrate, modulate, and interpose a temporal domain in the visual message presented to the retinal ganglion cells, with which they synapse in the inner plexiform layer. Amacrine cells lack large axons. [ GOC:bf http://purl.obolibrary.org/obo/CL_0000561 ]