Tetris (Game Boy)
The Game Boy version of Tetris is a very famous rendition and the system's pack-in game for American consumers. The game was so popular, it led to the Game Boy being a major success for Nintendo.
An unused level-up sound, present only in Version 1.0. Game Genie code 084-F5D-E62 will replace the existing sound upon leveling up.
Version 1.0 was only released in Japan as part of a Special Link Bundle, and is estimated to have sold around 25,000 copies. Version 1.1, used for the rest of the print run and released internationally, contains the more widely-recognized A-TYPE music and is overall a slightly more polished game.
Hyphens were added between "Bullet" and "Proof". Also, the copyright screen is displayed for just two seconds in v1.0; this was extended for v1.1 to eight seconds, although pressing Start after four seconds will take you to the title screen.
Music and Sounds
The A-TYPE song in v1.0 is Minuet. For v1.1, the tune changed to Korobeiniki, which essentially became the Tetris theme.
The "level-up" sound was changed from a simple beep to a short jingle.
Version 1.0 requires you to score 20 lines on Level 9 to proceed to Level 10. This was changed for v1.1 to 100 lines, much like most other versions of the game. This was presumably done as if the player started gameplay on Level 9, they would reach Level 10 as soon as they scored only 20 lines.
Block Rotation Glitch
Version 1.0 lets you rotate a block while clearing a line, multiple lines, or a Tetris if there is room in the playing field.
Input During Line Clears
As with the block rotation, v1.0 also reads the directional input during the line clear delay. This allows you to "charge" the Delayed Auto Shift which makes the next block start to auto-shift in the direction held immediately after spawning. This is very handy during higher levels. This also allows the player to trigger a minor sound glitch, by playing the short beep in response to the movement input and cutting off the much longer line clear sound effect.
v1.1 doesn't read directional input during the line clear delay, so there's still a pause before the next block starts auto-shifting, and no sound glitches can be triggered this way.