Anime as we know it was born out of the circumstances of post-war Japan, so anime if the 30s-style Imperial system had survived would be pretty much unrecognizable from what we know today. Animation was used by the Imperial government in the 30s and 40s as a form of propaganda, with cartoons that generally took Japanese folk heroes (Momotaro being a popular one) and depicting them as fighting off enemies that were usually thinly-veiled stand-ins for the USA or Soviets. Stylistically these were all quite similar to American animation, with the big-eye, rounded, cartoon look found in the works of Disney and the like. I can imagine that anime under a surviving Imperial regime would have largely stagnated stylistically, and would likely just consist of films and whatnot used to promote the imperial state and its various messages. More adult-oriented animation likely would not have occurred, due to social conservatism, and animation would therefore largely remain as propaganda made for kids. On the other hand, if we consider a timeline that involves something like a Taishō-style liberalization actually take hold in Japan and succeed, basically leading towards a "softer" regime, artistic freedom would be greater.