Great game! Just found a little bug that I would suggest correcting!
If I keep moving, my speed will start to increase the other way around! Meaning, if I keep holding the left arrow, as my speed gets to zero, I will be increasing my speed towards the right side. Therefore, I was able to exploit the game and complete all levels without the dash as I was always increasing my speed with reverse controls.
To correct it, not knowing exactly the platform you used to make the game, just set the variable speed to 0 if it is less or equal to 0!
Besides that, really cute and a great concept! :)