fist things first: really cool pixel art and presentation.
I would add a small tutorial to introduce the controls and the dash. It seems that there is no way to cancel the dash early. If this is intended I would add a visualization for the dash duration (e.g. a progress bar in the GUI or over the player.
The controls are a little bit clunky, I think the main issue is that the player speed adds up for horizontal movement. If I press twice to the right, I also need to press twice to switch direction from right to left. This can also be a valid decision, but then I would make the steps more clear and also add a visual indicator (other animation)
But great work for only 9 days! keep up the good work!