The popular anime visual novel DDLC programmed from zero in vanilla javascript, in order to make it playable in a web browser. It was my first big proyect, I started it when I had few notions of web development, so it's full of errors and terrible practices, but I managed to build the entire game and make it run exactly like the original with very few tools.
Some of the many concepts I handle in this project are:
CSS animations
Responsive Design
POO
Consuming data from API
Audio Handling
Image storage