These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Adaptation Displacement: The original version was released in 1985. The world-famous Game Boy version was released four years later.
Americans Hate Tingle: SEGA's versions of Tetris, while a historical staple of Japanese arcades, failed to find an audience outside of Asia, where Nintendo's versions (particularly the official NESnote there is an arcade version by Atari that was ported to the NES by Tengen, but it wasn't as popular and Game Boy versions) easily became an icon of classic gaming instead. Perhaps because in the USA, Atari had the arcade version of Tetris; after all, Tetris has been a legal nightmare for all those involved for decades. Had it actually been released here in the US, it might have gotten more popular.
A lot of players also love the I block because it's usually used to fill a gap that will result in getting a tetris (clearing four lines at once).
First Installment Wins: Any time someone brings up Tetris, the Game Boy and NES versions almost always come to mind. Subverted at the same time, in that these aren't the original versions; the first version of Tetris was released on an Elektronika-60 computer in 1985.
Good Bad Bugs: Sega's 1988 version of Tetris uses the exact same RNG seed every time the machine is powered on, resulting in what is known as the "Power-On Pattern". With some planning, you can take the guesswork out of achieving high scores, especially the maximum possible score.
It's Easy, so It Sucks: Some fans dislike newer versions, particularly those that use the "bag" randomizernote each group of 7 pieces is a randomized permutation of all 7 tetrominoes, as a measure to avoid piece droughts, because they avert the Fake Difficulty caused by a completely random generator (e.g. a large quantity of S and Z pieces and a drought of I pieces).
The I block has it, too, mostly because it's the only one that can get a Tetris.
That One Level: The Crystal Tower levels from the Hide n' Seek mode in Tetrisphere, which appear rarely, only in later chapters, and always as the last level before an actual Hide n' Seek level. In Tower levels, you have to expose a picture at the bottom of the tower by moving and destroying the blocks covering it. Crystal Tower is the same, but destroying a block next to any part of the tower (or carelessly moving a block into it) also destroys that piece of the tower, which is an instant Game Over in a game that gives you three lives per level. This means any chain reaction that makes its way to the tower is an instant fail, even if it happens under the layer of blocks you're looking at.
The infinite spin mechanic, which some players feel makes high scoring runs trivial. To wit, there is very little difference between playing a survival-style mode in level 0 compared to playing it in level 20+. The only differences in that latter is you have to keep rotating the piece to keep it active and cannot "climb" walls of blocks. Timed and competitive modes are less affected.
In Tetris Friends Marathon mode, a 15-level score attack mode, the scoring system is particularly biased against Tetrises. To be a little more specific, doing 2-combos of singles and T-Spins yields more points per Goal unit than a Tetris, which takes off 8 units and therefore causes the game to end sooner.
Many of the games give an enormous amount of points for clearing lines using a T-Spin, to the point that the highest scoring games revolve around setting up T-spins for every line. While there's skill to it, this can feel like downright Gameplay Derailment for those used to just trying to get tetrises in the old games. Alternatively...
Most of the older games gave an enormous amount of points for tetrises (clearing 4 lines simultaneously). Mixing in some double and triples adds variety and doesn't take away from the challenge (aside from making one less dependent on I-pieces), but should not be done if going for a high score in these games, since the tetrises are worth far more per line cleared.
What Do You Mean, It's Not Political?: It's been argued that the game is a metaphor for life in the Soviet Union. The "Complete History of the Soviet Union" song plays this angle for all it's worth.