Here is the full list of all 10 Touhou Block Fall ~ Yukari achievements.
Start your first game.
Make 100 gaps.
Make 500 gaps.
Make 1,000 gaps.
Match 500 blocks.
Match 1,000 blocks.
Match 2,000 blocks.
Make 300 gaps of at least 3 blocks.
Make 200 gaps of at least 4 blocks.
Make 100 gaps of at least 5 blocks.