First we have the original version for Electronika 60 and PC. this rotation system is the original. CCW only, and the states are identical to what we know of as right-handed nintendo rotation, except that the horizontal I is one block higher. No soft drop, only hard drop. no lock delay, gravity lock (if the piece is moved to overlap a piece going down, the move is canceled and the piece is locked) Spectrum Holobyte's version (actually by Mirrorsoft) decided to improve this. All pieces except the I were lowered to the bottom of the bounding box, to allow for rotation on the ground. They also used entry reset, to give you about a half second or so to slide a piece if need be. Next, we have Atari and Sega Tetris. Atari used a strange left based system and was quickly forgotten. They did introduce the first wallkick, to make up for the left bias, and gave soft drop instead of hard drop. No lock delay, though. Sega made some refinements to the rotation system already in use for PC Mirrosoft Tetris. They made the S round left instead of right, and introduced step reset, replacing the entry reset system from PC tetris. This was a major improvement over entry reset, and pieces would still rotate after landing if needed. They also used soft drop instead of hard drop. Still only ccw rotation for all so far. Later, Nintendo goes back to the original rotation system and decides to make their OWN improvements. They add rotating both directions, since their consoles had 2 buttons. BIG improvement here. For some reason they made their first one left handed instead of right. They also lowered the I down by one square to make it easier to get the I piece to the side (this raised the starting bounding box position). The NES version went back to right aligned. They too, use soft drop instead of hard. So now we have the big divergence. Sega rotation and nintendo rotation evolved independently from the original. A bit later, BPS starts improving on Nintendo rotation. they introduce 4 state for all pieces except the I, and independently add step reset. They also decided eventually to flip the initial orientations over for L T J and I, to make mobility easier. SO we have BPS 4-state. Meawhile, back in Japan. People take Sega rotation and run with it. Tetris Plus, Tetris Plus 2, and the never sega tetris all use sega rotation. They add clockwise rotation, but other than that, very little is changed. Then someone from a little company known as Arika sees Tetris SemiPro 68k, and this inspires him to do better. He fixes up the flaws in Sega rotation. he removes the rotation ceiling, and invents initial rotation system. He also adds wallkicks, which nudge the piece a little bit to the side if it can't rotate to try and help you out. This is tgm rotation we know and love. BPS and Nintendo keep experimenting. Tetris DX has a system of alternate rotation centers, to try and allow more rotations. It also is much more forgiving about sliding pieces, as I recall. On the BPS side, we have an experiment with The Next Tetris. This attempted to apply real world physics as best it could, and introduced Infinity. The basic rotation was never used again, but move reset was here to stay. For N64, we had The New Tetris, which introduced Bag (63 piece version) and is the beginnings of SRS. there were some wallkicks, but they weren't all there. We also have twist detection. Finally SRS is developed, and shows up in Tetris Worlds. Full infinity, crazy wallkicks, and 7 piece bag. This unifies all of nintendo and BPS together, but ignores Sega rotation completely. Arika continues to improve Sega rotation, and creates TGM2. This gives us sonic drop. TI is further improved, adding a few more kicks which make mobility of the I and T pieces better. I know there is much that I haven't described here, but this is pretty much how things developed, i think. Instead of bringing people together, SRS fragmented tetris permanently. By making the wallkicks system completely incompatible with Sega rotation, they broke all possible ways to include it. DTET rotation system is actually much more of a unification of nintendo rotation and sega rotation. It still doesn't have any of SRS's crazy kicks, though.
Small error: T+2 (Tetris Plus 2) actually has a rotation system *almost* identical to that in TGM1; in T+2, the wall kicks and floor kicks work exactly the same for all pieces but I in both games, with I having wall kicks in T+2 but no floor kicks. Even the kick order is the same, with "Mihara's Conspiracy" moves possible in T+2. T+2 also has no rotation ceiling, but does lack IRS. This has lead to my own theory that Mihara copied the rotation system in T+2 for TGM1, but changed it up a bit. Fixed up for the wiki, this would be a great wiki article.
I have a file on my desktop called "Tetris Firsts.txt" that outlines similar findings if anyone wants it. It is more focused on when certain features first appeared and sort of skips out on certain aspects of rotation system development, -- the note on 1989 GameBoy just says "randomizer balancing" -- but it may also come in handy in developing some sort of family tree.
Another small correction: I'm pretty sure that the PC version by Spectrum HoloByte (the one with rotation very close to what we know as SEGA rotation) was indeed developed by Spectrum HoloByte themselves, and not Mirrorsoft. It was the C64 version which was developed by Mirrorsoft, but distributed both in the UK by Mirrorsoft and the US by Spectrum HoloByte. Also, what we call "Atari Rotation" was actually first featured in this C64 version, albeit without the wallkicks.
How is DTET rotation a hybrid of NRS and ARS? From my point of view it's just a symmetric version of ARS with as many non-upward wallkicks as possible.
Well, considering that John Jones-Steele programmed BOTH the Mirrorsoft version AND the Spectrum Holobyte version on Amiga... http://www.mobygames.com/game/tetris/release-info Things clearly aren't that simple. So I'm inclined to go by the readme (TETRIS.TXT) that states that Spectrum Holobyte is merely the distributor.
I'd love to see a video of this (and Kitaru's fule), with explanation of what is which game mechanic. And a logo of TC with that Also Sprach Zarathustra music piece. ... in the ideal world there would also be TGM4,5,6, no wars and I would be good at Tetris.
