Many javascript code compression techniques are used to create even shorter demos, animations and even games, using 140 characters or less, by the Dwitter community. E.g. a similar to Perlin noise image used to create the terrain (in this 13k game) was made with less than 140 characters of JavaScript, see here: https://www.dwitter.net/top/month Some Dwitter members are also developers of 13kb games.