Here is the full list of all 32 Inline achievements.
Spin one shape 20 times
Reached more than 9000 score in total
Skip a single block
50 lines cleared in one session
Reach a combo of 4
Use the Gameboy command in the console and enjoy tastelessly emulated graphics from the past
Beat your own highscore 3 times
Reach level 5 without skips
Rotate a shape that will not change the orientation
Drop a shape outside of the grid
Play Custom Mode
Click and hold main menu title for 5 seconds
20 skips used
Reach level 5
Reach combo of 3
Skip when no more skips are left
Reach streak of 3
50 shapes placed
Lose with no lines cleared
Reach max level 10
Lose after using 5 skips in a row
Play 20 normal games
Completed 3 lines in 9 moves
1000 lines cleared
Reach streak of 5
Reach 600 score in 50 moves
Find every easter egg
Type RAIN at the main menu and let the rain work its magic
Repeatedly press ESC at the main menu to display the game with inversed colors
Try to access debug features and meet their guardian
Push an AI to crash the game
Find the option hidden in the options menu, and enjoy them "soft-body physics"