So I just booted up my ol' Windows Phone to carry on playing Tetris Blitz and found a pretty handy cheat/bug for anyone who wants a quick 200 gamerscore.
- Simply play the single player mode up until level 11, until "Tournament" mode unlocks. (This should take around an hour or so of play to complete.)
- Pick one of the daily tournaments, preferably one of the easy to score in modes such as, "flash flood" and play through it once.
- Afterwards in the "Tournament" menu under "Your Tournaments" select the "Details" option and watch any of the other players run-through of the game.
- Any achievements that they gain will then become yours, just by watching through the video.
I found this purely by chance and have no idea if it is documented anywhere else. I also have no idea if the developer is even aware of this bug?
Hope this tip helps, if it does please leave a comment below. :-)