This is a time-lapse of me developing CSS game using "only CSS", no JavaScript or HTML. Truly, there are two HTML elements on the page: the html and the body, that are injected automatically by CodePen (the editor).
The coding process took around two and a half hours, this time-lapse is at 20x (~8 minutes). I will upload a longer version with explanations and more details.
The game uses animation and transforms that combined make WebKit browsers (Chrome, Brave, Safari, etc.) struggle a little. If you want to check the demo yourself, it may be better to do it on Firefox. If you use WebKit, try to make the screen small, and/or reduce the resolution in the game (instructions in the comments).
Link to the demo: https://codepen.io/alvaromontoro/full...
Link to a Twitter thread explaining the process: / 1342524426785607690 (follow me on Twitter for more demos, including some not shared on Youtube 😉)
I will add a DEV post link with more details... once it's written and published.
Music credit: Happiness, by Bensound.