Here is the full list of all 12 Unblocking achievements.
Complete all levels of Puzzle Pack A
Get a total of 200 points on Relax mode
Use 10 power-ups while playing Arcade mode
Complete all levels of Puzzle Pack B
Play a Relax mode round for 12 minutes
Do a combo of 3 lines 2 times in a row on Relax mode
Complete all levels of Puzzle Pack C
Do a combo of 3 lines 2 times in a row on Arcade mode
Catch all bonus blocks on Relax mode 5 times on a single session
Complete all levels of Puzzle Pack D
Play an Arcade mode round for 15 minutes
Unlock all hints up to level 40