The up arrow to store was the biggest problem for me. I ended up doing this about 10 times in about 40 pieces, just because it's muscle memory from Tetris.
Same here. Also, such games would certainly benefit from single-hand operation in mind. I'd prefer UP for rotation, DOWN for drop, and, maybe, PgUP/DN for L/R rotation, END for hold. And similarly on the WASD side of the keyboard, so either hand may be used optionally. Or even for one-keyboard multiplayer. )