This is a powerful setting. The broken up remains of a planet and people desperately relying on magic to survive. Its definitely a situation in need of heroes! This is a difficult setting to work with and the author presents a deep and thorough portrayal of challenges, places, survivors and new magic.
If you want something very different for your group to explore this is a good choice. Its packed with writing and gives a DM a lot to think about. The rules for replenishing air and survival in the void would make an interesting addition to any planar adventure. I found it a good balance of playability and physics, after all magic enables the impossible. I think DMs who want background for truly strange locations will enjoy this setting.
Doesn't the DM need an answer for what could happen after everything blows up ? :)
Perhaps vital magics to your plot line have survived the great cataclysm and must be retrieved from the inky bleakness of void? Perhaps your high level mage is approached by displaced survivors from Broken who want to create an escape portal for their families or a battleship for conquest?
It's a rich description and a great option to have if your own setting really, really, goes KaBoom!
My chief criticism of the piece is that it isn't bookmarked and the author may have tried to do too much. Its a one man show with great writing and inspired but perhaps over ambitious art work. The cover is great but some of the internal art is amateurish. These flaws are not crucial but I think they mar a great PDF. I hope the product life will allow this to be addressed with a revision.
This has many different options from the standard little town or regular city. The setting could be adapted to many genres (some posters seemed interested in resurrecting Spell Jammer). Broken would make an admirable alternate universe setting, where something went drastically wrong. It would make a good source for refugees in need of rescue or even a cruel punishment plane created by a fickle deity. It might be a ruin the characters survive or a retreat for a powerful demigod who hates people. The core value is there and the work is very original.
In an overcrowded PDF marketplace this is a gem with some rough edges - but certainly a gem.