Unfortunately for now, there is only one zone. I will be working on making more content (The free story mode is planned to be 8 characters over 7 zones), but I've got a few bug fixes and small features to add that the community requested first. I'll try to rotate between bug fixes, features, and more content so that everybody benefits.
Thank you for playing!
(The text that shows when you hold/hover on the Oasis tooltip is initially "Complete Glades to Unlock!". Now that you've beaten the final boss, it should say "Available in the next* update!")