I enjoy the gloomy aesthetic and art style, the character also looks nice, and the story is good as far as I played, though I think it was a bit long-winded with the exposition text.
The boss was way too difficult, and the controls weren't tight enough for such unforgiving windows to dodge the spikes. There was a significant delay on attacking, and the extra momentum after you stop moving makes it very easy to be stuck in place and get hit- or slide into the spikes while they're active. The projectile the boss fires often comes from off-screen making it very easy to get hit by as well.