Finished it. The ending speech was pretty cheesy.
I like your level design for the most part. You did a good job with introducing new challenges as the game went on.
The collision detection seems a bit rough, with the collision boxes feeling larger than the sprites making some of the challenges a bit tougher than the seem.
The turrets firing randomly instead of in patterns is horribly, horribly annoying especially in the few levels where you need to drop past turrets in a small vertical tunnel.
It is not intuitive that you need to jump in order to round "outside" corners, especially after a stretch of "inside" corners that you can walk around with just the arrow keys. Pressing jump on a wall making you fall without jumping and only letting you actually "jump" in midair once after doing so is also not intuitive or consistent with the ground behavior.
The graphics work well functionally, apart from the active red spikes blending in with the background a bit.