It's definitely not just the design itself. The CTA (your email submit) of the new landing page is better positioned throughout. You have also added urgency ("time until next shipment", "subscribe now before time runs out"). You can also see up to 3 previous candy boxes now, whereas before, you'd have to click through. All of those contribute to the conversion rate of your new landing page.
Your old landing page actually contains some great elements that are missing from the new one, like the reviews, the explanation anime video and the "new tastes only available in Japan", which seems a great feature to me. I'd definitely try and add those back in, and split test that new version against the current winner.
Your old landing page actually contains some great elements that are missing from the new one, like the reviews, the explanation anime video and the "new tastes only available in Japan", which seems a great feature to me. I'd definitely try and add those back in, and split test that new version against the current winner.