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