The parallax effect is enherent to old school raycasting. And I'm agree that it gives a nice retro feeling. If you are interested in how it's done, I used this tutorial and rewrite the code in Typescript.
Alas! I did not had time to add some interesting secrets in this version. Maybe I can do it in a post jam version.
About the story, There is not much detail, but you're in a mine, seeking for treasure. The creatures are here to extract emeralds and are defending the mine. The 'doors' are more like little defense tower. I needed some still enemies for early game. I really wanted to add more kinds of enemies with all kind of behaviors but I ran out of time.
Thank you for playing and commenting!