The Tetris clone that comes standard with gnome is hard-coded to have 14 columns. That’s a LOT. It makes the game much harder to lose, and much easier to drop the piece in the wrong place.
I might as well go all out and play it here: ridiculously huge flash Tetris game
I’m much happier with KBlocks. It has ten columns, which is very acceptable. It took awhile to install since it depends on many KDE packages, I’m assuming. Bonus: its default theme is an awesome Egyptian style.
sudo apt-get install kblocks