So it'd work like a dungeon (or world) adventure game where you can all explore, theres a 'hidden' map thats slowly discovered after exploring.
You'd each get a set amount of stats to apply to your character/player at the start (this would be free unless you want character art ^.^)
While exploring you may discover creatures that can help you, come across merchants selling eggs or pets and so forth. You can collect different species, breed for mutations and battle for fun, riches or territory!

(Image doesnt belong to me! https://i.pinimg.com/originals/59/27/d3/5927d319970144be69d47b80acb9f063.png)
Maps would be layout like this but would be revealed as players explore ^.^
Who would be interested?