Visit the place again. There's still ample construction machinery around the open end of the park along the walls and almost no animals within. It's clearly something that's a recent addition to New Mombasa and as of the Covenant invasion; it's not quite completed. That's how I've always seen it...if the park was done and operational, why all the cranes and scaffolding and half-built architecture? Did I miss something? It really gives me the impression that it's not complete. I expect the final structures to be fully round.