The jump mechanic is quite innovative, the only game that comes to my mind is YMM's FLaiL though the arrow keys were used there. I think the game mechanic when the player character becomes red and invulnerable after double jumping is fun!
Have you thought about clicking in the direction to double jump (instead of the opposite), to make it easier to aim?
The color scheme actually has its charm, brings some nostalgia. And it's cool how the pool of lethal liquid has eyes.
That's actually the last room. The difficulty's a little over the top there. When I expand this, the difficulty curve will be a little smoother.
I think the difficulty was pretty all right now when we get to restart in the beginning of the screen.
For the final version, I'm considering not even having a projectile; instead, you just fire the laser at the mouse cursor.
I think that sounds like a good idea.