For quizzes 1–26, this is how many islands belonged to each continent: Europe 110, North America 87, Asia 81, Australia & Oceania 67, Africa 38, Antarctica 17, South America 16. For more statistics on the whole series, check out my (as of writing not yet published) blog post!
First one I didn't get any on. I recognized the shapes of Banaba and Vaygach but couldn't think of the names. I've also heard of Grand Turk, Catanduanes, Prince of Wales, Edgeøya, and Xiamen but didn't know what they looked like.