For the crank, I meant in addition to the A and B buttons to rotate the pieces. Selection would still be on the D-pad. Anyone who doesn't want to use it can leave the crank docked.
For the System menu, you could put the Settings and Achievements entry points. Then the main screen could be just Start 1 Player, 2 Player and How To Play. (I also don't think I understand how the piece cascade is supposed to work. I do beat the CPU — sometimes!)
But I get it. Getting to "done" and publishing a game isn't easy! Congratulations!