PC title Dwarf Fortress may well be one of the ugliest video games of all time. It does make for one hell of a lovely picture book, though.
An introduction: before there was Minecraft, there was Dwarf Fortress. It's part world-builder, part-RPG, the product of one man and, in its raw state, played using ASCII art as though we'd never left the 1980s.
Don't sell the game short on its visual shortcomings, though; it's a deep game, and a thriving community has sprung up around it, at its lightest serving as the glue that holds an otherwise primitive game world together - at its densest coming up with stuff like this: Matul Remrit, the illustrated tale of one particular game of Dwarf Fortress.
Of all the things I love about video games, this is thing I love most. Games that set their claws so deeply inside someone that they don't just play it, they live it, coming up with stuff like this in their spare time.