Brawl does not store a full-size image of your stage inside the stage file; it only stores a thumbnail like you see above. The blurriness is the result of enlarging the thumbnail. However, BrawlSnapshots.com lets the submitter of this stage associate a better resolution snapshot with it by clicking "Edit" and then "Pick a Different Snapshot", so bug MrX8991 to do that for this stage.
This stage is designed around long range projectile combat. For those with terrible jumping abilities, there is a tunnel under "No Man's Land".