If you wanted to cut to the chase, you could say Obsidian is a game where a computer goes rogue and tries to destroy the world. There’s lots of stories like that, and technically, that’s where Obsidian ends up too, but the path it takes to get there is mind-boggling.
The longer version is that Obsidian is a game where a computer learns how to imagine, where dreams take on dizzying, literal form, and the end of the world is just a chance to reinvent it. Adventure games have a history of packing complicated puzzles into strange places, and using that same format, Obsidian asks the question whether it’s a good idea to dream at all.