Does not boot in Nintendulator. Tested in FCEUX. Not yet in front of a PowerPak to test with.
The menus
Title screen - "TETRIS" logo should be changed. In this state I can't even link to it on harddrop.com, which bans links to sites offering downloads of video games that obviously infringe the Tetris trademark.
"Karinka" - Just as expected. Where there's an R, there isn't a slowdown in the verse.
"Technotris" - expected "Arabesque" written by Burgmüller, but it's "Angels We Have Heard on High".
"Korobushka" - more repetitive than even the GB version.
Obviously they want players to pick "Karinka"; that's the most fleshed out of all of them.
Game Stah-to-to!
Screen is monochrome, but the left third of the screen is "prettier" than LJ65. Game Boy homage?
Sideways shifting is slow, unlike another famous Japanese Tetris game.
Both B and A buttons rotate clockwise.
No soft drop. Down on the Control Pad does "firm drop", as seen in The New Tetris, Tetris The Grand Master 2, and Tetris The Grand Master 3 in "classic" mode, but there's no way to manually lock a piece down.
No wall kick; it's hard to turn pieces close to a wall.
Pause and the field remains visible.
"PRAYER 3"?
Overall quality of game rule implementation matches a typical JavaScript game.
I'd submit a bug report, but I speak no Japanese. So for now, I'm sticking with eating
my own dogfood.