Well I've finished a game on the 'easy' difficulty, and easy sudokus usually don't require writing candidate numbers all over the grid after placing 2 definite numbers. But your Web site does note that the difficulty levels are not well calibrated.
Given the emphasis placed on putting candidate numbers all over the grid, why not make Y toggle between annotation mode and definite number mode, and in annotation mode, not lock the entry to one cell? That would make moving around the grid in annotation mode so much easier.