If you are looking to the game, it is safer to download the official app or play on established web portals. If you are looking for informative content (code and mechanics), searching GitHub.com for "Crossy Road clone" will yield the most educational results.
The .github.io version will likely remain online until a DMCA takedown. Its maintenance is minimal – no new features, bug fixes, or security patches. As browsers evolve (e.g., phasing out requestAnimationFrame quirks), it may break. crossyroad github io