You have to clear the EX stage of the first Tetris Road (Big Road) for this achievement.
To get to this, on the main menu:
2nd option (Xbox Live)
3rd option (Create a Session)
Top left option, set it to the 2nd option from the top, which is tetris road.
Then select the top most option. This will search, come to a miniature lobby, and then load the game with a 15 second countdown.
You will only have one option (Big Road) selected on the road selection if you've not completed any Tetris roads before.
You have 5 stages in this road:
1) Big - Get 10 lines (1 minute time limit)
2) Tetris - Get 5 Tetrises (2 minute time limit)
3) Cycle - Get a Single, Double, Triple, & a Tetris, in any order (2 minute time limit) (After this stage, the play area will be cleared)
4) Big - Get 20 Lines (2 minute time limit)
5) Level Star - (1minute 30 second time limit)
MAKE SURE YOU COMPLETE THE FINAL STAGE WITH A DOUBLE-LINE CLEAR
If you do not, you will not be able to get this achievement on this playthrough of this Tetris Road.
If you finish stage 5 (Level Star) with a double-line clear, you'll get the EX stage...
EX) Big - Get 20 lines (2 minute time limit).
If you manage to complete the EX stage, you will unlock this achievement.