Tetris Evolution

While TheHippieRipper's solution is good, it wasn't working for me. I couldn't control the drops very well at level 10, so here's how I did it:

Mode: Marathon
Target: High Score
Start Level: 1
Fill Start: 7
Fill Rate: Medium
Goal System: Variable
Lockdown: Infinite

Once you start, clear as many dark lines as quickly as possible. Once you reach the bottom, start building for Tetrises. The more you get, the quicker you'll level up. Once you get to about 3/4 the screen filled, aim to quickly clear any and all single lines you can without ending the game. I got to the very top, clearing the last line 5 times before popping the achievement.

Takes a lil practice, but don't give up. Bronze is attainable. Silver will take some work. Gold, for me, is next to impossible, but I'll keep on working on it. And once I get any more tips, I'll post them here! :)

Easiest thing to do is to set the level to 10+ and the fill rate to 4-6. You get more points for the higher the level you are and it takes 100 lines to level up from level 10 to 11 so it's an optimal time to score.