Most notable for its background music. It is one of the worst tetris implementations ever made other than that. 1 rotate button, no hard drop, and no twisting of pieces at all. even if the initial and final squares of a rotation are free, the peice will not rotate if it is against a wall.
Another version was programmed by Hungarian developpers. Catched the eye of Robert Stein along with its Apple II counterpart, which triggered the release of Tetris outside USSR.
This was the first version of Tetris produced by Mirrorsoft for the commercial market and was converted from a CBM PET basic program (this is the acutal one written by the Hungarian programmers usually mentioned which contained no sound, no graphics beyond character set gfx and no "next" box) into machine code by a British schoolboy working out of his bedroom. He was paid the princely sum of £50 for several months of effort. As there were no other versions in existence to compare it to, that is why some of the gameplay is different.