I had some real difficulty with the keys. My mind is so used with move on the left (WASD) and action to the right (mouse) that having to press F and shift got things funny to me lol
Also, the change in speed with shift is a little tricky... I thought everything would go slower, but actually things goes slower and you go faster! It is hard to control the player while holding the shift key and than you need to wait until the bar is completely filled to use the slow again, what can be an intended feature, but felt a little frustrating. But again, my brain didn't work very well with these controls! lol
Pretty good job! Keep it up!