The Crystal Mask of Wisdom by Rob Beschizza is an entire video game that fits in an 8×8 pixel box (that’s smaller than a favicon!).
The empire of halxe is in despair and dragons scour the land. Search for the Sword of Maguss in the forest of foiwn. Locate the Shield of Doom in the tomb of peuxbe. Collect the 16 rings of power and find the key of souls to unlock the secret of the pinnacle of pain, where the evil Tharg gathers forces for the final attack.
It’s a must play, if for no other reason than to be impressed by how much gameplay they were able to cram into such a tiny space.