Here is the full list of all 8 Gridlock achievements.
The base game contains 0 achievements, and there is 1 DLC pack containing 8 achievements.
Complete your first game
Score 100 or more in a single game
Score 500 or more in a single game
Score 1000 or more in a single game
Reach a 3x combo
Reach a 5x combo
Clear 100 lines
Complete 10 daily challenges