Complex sentence: Wells describes a multiverse of alternative worlds, complete with the paratime travel machines that would later become popular with U.S. pulp writers, but since his hero experiences only a single alternate world this story is not very different from conventional alternate history.
Split into simpler sentences: Wells describes a multiverse of alternative worlds, complete with the paratime travel machines that would later become popular with U.S. pulp writers. However, since his hero experiences only a single alternate world, this story is not very different from conventional alternate history.