Sonata Op. 36 in B-minor

Which differences there are between Rachmaninoff´s 2nd Sonata´s original and revised versions? Is the original version more difficult?

Yes, and no. The material doesn't change, there's just a lot less of it. He basically took a hacksaw to his masterpiece and the revised version runs like a highlight reel. The wonderful polyphonic bridges, which -are- difficult to say the least, are replaced with teleport pads.