Fun game. I feel like the speed gained by the power up should just be the default move speed. Also I noticed that the big red apples subtract from your score which is part of the deception if I had to guess and not a bug =D The game is good and would be even gooder with some more juicy visual and sound effects on picking apple. Cool stuff. Well done.
EDIT: I just read your description of the limitation and yeah it turns out the slow move speed is becuase I died a lot lol