Some more flaws with GB tetris:
when the piece is moved to the edge of the screen, it cannot be rotated which is incredibly frustrating at high speeds, On Acid tetris, it simply moves sideways until it can be rotated.
And I personally think that all the extra gimmicks they add to tetris doesnt enhance the gameplay at all, the pure, simplistic version is always the best.
Also, for those of you who only get tetrii: You are missing out on a whole other dimension of the game simply due to the fact that lines do not dissapear when you "almost" score a line so that there are a lot of situations where a piece could be put so that it would make a hole but then the hole would open un due to a line being scored. This is missing by people who only score tetrii thus making the game a less profound experience. just my opinion of course