Well, I downloaded Hacker Tetris because I was looking for a tetris version, where I would not be forced to quit because of incredible falling speed. In all tetris games I've been playing before the speed increases just too fast. In Hacker Tetris it is very pleasant for a long time, but at some point, it just is not controllable any more.
However, the most times I quit because playing wrong, building too high, waiting for certain stones to fall, avoiding making single or double rows, and then I realize that the stones I hoped to fall just aren't falling. Well, that's randomization, and my bad playing.
But sometimes I really wish to have a tetris game mode with constant falling speed.
Another nice feature would be a possibility of dropping stones not fully but just partly - in case you want them slide under some other stones. Now in the hacher version now you just have to wait until the stone falls down the whole way by itself and the slide it in the last moment. That waiting is boring. But stone sliding on the ground is a pretty good technique. On Youtube is a sample video
of some quy marvellously exploiting this.
Such a playing mode - like in the video above, where the stones are not falling, but are readily laying on the nearest ground waiting for the player to fix them in the desired position would be fun to play, too.
It would be great to have a thes tetris on PC. This mode AFAIK is only available for Nintendo.