Nice way of using the one control rule.
I quite like that you added multiple difficulties and the mechanic of holding down space to continue moving in your chosen direction in nice so you dont have to keep waiting for the arrow to come around.
An idea might be to add the arrow as a transparent overlay to the centre of the screen or add it to the player sprite, just so the player doesn't have to keep looking up to the top left whenever they want to move. I also noticed the tiling on the trees looked a little off, perhaps it's just my resolution or something, but I noticed I could see the border of each tile a little bit. I also managed to get myself stuck in the top right corner of the map so perhaps some of the colliders need to be a little more strict.
Overall nicely done! Impressive how much you managed to do with such a simple control scheme and prompt.