I've read through the
rules for 2018 and there are a few changes for the NES competition("round zero" 1on1s on Saturday to determine the last 8 spots in the top 32, starting level must be 15 or 18 from top 16 onwards). But the most interesting change involves SNES Tetris.
In the past few years, the SNES tourney was declared as an "amateur" competion. That means participants for SNES weren't allowed to compete in the other Tetris competitions (e.g. NES), thus the starting field was nameless and there wasn't any footage of the competition.
This year, there isn't even a SNES tourney. This doesn't necessarily mean that there isn't one in the next year but I don't like the direction it is taking.
Multiplayer is treated as an orphan at CTWC. SNES would be a good choice because it is classic, it uses the same rotation system as NES Tetris, and the versus mode is well made. Last year, Sega sponsored CTWC but still no Puyo Puyo Tetris.