I think that it would be beneficial to avoid restricting areas with spikes, and instead make the obstructions seem more integrated into the environment.
Also, I have no clue what those targets were supposed to mean, as one time it seemed to be pointing you to the exit, and another, it seemed to just be decoration.
It would be good to know what your health is
I also think that it would be good to have a physical indicator of whether an enemy has taken damage, whether it be from a health bar above the enemy, or from a change in the sprite to have the enemy look more battered.
The stairs are very clunky.
I found that it is very inconsistent as to whether you can do the dash, and from the animation of the dash, it seems like it should do some damage, as you turn into a spike, flying at an enemy, and since the enemy (or at least the flying enemies) reacts to your attacks, it gives the impression that your dashing actually deals damage.
Attacking with your melee seems pretty useless compared to the dash, as it seems to have far less of an impact on enemies
I think that it would be a good idea to have some sort of indicator as to whether you have reached a save point, because sometimes when I die, I am confused as to why I spawned where I did.
The last two rooms seem to be very similar and hard to differentiate
The spikes should deal more damage, or have a different effect on the player, as in the third room, you can just walk across the spikes without dying to the exit, with plenty of health to spare.
While staying in the dash, you should make the falling downwards more powerful, as it feels like you stopped time, instead of just slowing it.
Otherwise, nice game.