Late game idea or even early game. Have two or more hidden gateways either deep in the planet or near the surface. I would keep it at two gateways though. Probably would be best randomized on different planets. Say have one on Desolo then one on Atrox. Would be a super easter egg find. Would force people further explore deep underground. Possible settings in the UI a user could permanently change to easy mode to find the gateway like nearby, teathers would glow Green or Blue indicating the gateway may be buried. Possibly have certain types of plant life near the gateway to help reveal location as well. And the way to unlock it would be a with a special zebra ball, maybe of a different colour, which could also be in different planets not with the gateways. The artwork underground is super amazing and I just don't see anyone really enjoying the depths of each planet. The reward for find the unique gateways could also get you a very special suit skin to only be used on that game save. At least I would enjoy exploring the depths of a planet to find this super hard Easter egg. Which should be damn near impossible as I wouldn't know which planet either one would be on.