Or slightly before this, get rid of garbage canceling. Which allows a sufficiently autistic player to play slightly behind and memorize the other player's piece sequence, or to play slightly ahead and memorize the other player's garbage sequence. I used to do this all the time with garbage in Tetris & Dr. Mario: I'd send garbage to the opponent, watch for it to show up in the other player's field, drill down to the corresponding hole in my own field, and then tetris back any garbage I got, which was useful with the (now ridiculous) way that game's garbage was aligned. But even with random garbage, knowing what's coming next would help with T-spin forecasting. I believe that's already part of the guideline. Tetris DS already appears to do nearly this, inserting about 31 frames for a single, 32 for a double, 33 for a triple, and 34 for a tetris. (Lockjaw does the same thing.) All three versions on the NES (BPS, Tengen, Nintendo), plus the Game Boy version, have zero to negligible additional delay per line after the line clear delay, and so does TGM. In fact, the only Tetris product I can think of with a delay roughly proportional to number of lines cleared was Atari's arcade game.