What you've built is really great. What I so often find is that I spent 90% of my time on the game engine then the remainder building content. And it never feels like there's enough time. That said the atmosphere was spot-on. The mechanics are also great, loved the 3 hit combo you can perform.
The parallax is sweet, although a bit too fast moving (stuff in the background should move 'slower' than the foreground). How did you do it? I always struggle with parallax, although my games are usually top-down rather than side-on.
I did find myself wanting more so please continue with this one!