I was thinking about what would make the simulation a bit more progressive as mission's or achievement's & to have some things as an Easter egg to find.
1. How about adding the existing rovers in their current locations to find and/or a mission to repair broken ones like Spirit or doing maintenance on Opportunity. Finding the UK's lost BEAGLE lander ect. within an estimated area of its crash site. This would be highly realistic and fun.
2. Easter eggs (or whatever) such as finding foreign nations monitoring equipment or lander nobody knew about already on Mars. Save it, destroy it, or investigate it as to what is it looking for or has found.
3. Lost caverns maybe to explore?
