Spinning in some directions while touching the walls doesn't work, the board is shorter than I would deem necessary (apparently the NES version is 2 rows taller), controls feel unresponsive at higher levels/speeds and you can't place pieces fast enough on the sides when the board starts filling up (could be the 3DS emulation, or the impossibility to comfortably hypertap on a 3DS). It's still classic tetris, so its core gameplay is good, but it shows its shortcomings the more you approach the skill ceiling