Exploration: Moving resources a little further apart would also help.
Discovery: You are alone, this place is abandoned for a reason.
Combat: The red turrets are not pleased to see you.
This suggestion feels almost inevitable in a way, and it would lead progressively towards a more immersive world. I'm willing to aid with writing logs if need be. This idea is partly based on the Ruins mod, but also on the idea that the game could go in the direction of having an underground map for caves. The only drawback I can think of is that the aliens would need to have reason to ignore these places. Perhaps the aliens are focused on sound or electrical energy and the bases are mostly dead. Perhaps they are blocked off or otherwise concealed, or just further from the alien clusters. In any case, here are some possible barriers and interesting new items you might find in these places. Some could be unique to ruins in order to further push exploration (which is very lacking right now):
Shield generator. A very high energy end-game defense for critical parts of your factory\bottleneck blocking\etc. This would create a wall of light across the terrain between towers that are several squares apart. The towers are weakpoints. This idea is based on the concept that the aliens will eventually use tactics, target specific key buildings (such as high energy producers), and become hostile to the player as the game progresses unless the player works to mollify them.
Railgun sniper. Another high power weapon. Very slow charge up, targets a single large creature for devastating damage. Based on the idea that the aliens could eventually have huge armoured walking units that have a single weakness you must snipe. Maybe a siege launcher that hurls smaller creatures over walls.
Broken-down machines. These are permanent broken belts, machines, pipes, and so on that can only be salvaged for resources. Would also include scorch marks that are permanent until built on. This would also include unpowered 'fast' belts that require electricity (I'm assuming fast belts will be powered objects at some point).
Alien walls. Flesh or bone walls that are weak, but attack the player. They might look like curved hooks poking up out of the ground in ridges.
New types of base that could be used:
Precursor monuments. The age old 'highly advanced race came and lived here for a bit then vanished' idea. These monuments would be black with a gold 'circuit' design. Their purposes could be multiple. Dissemble them for gold blocks that can be used for high-level computer research, or use the advanced machinery yourself. These ruins would be small, rare, and highly defended. They could, however, yield exotic technology that is difficult to reproduce.
Water citadels with floating tech. They may have been part of an ocean going research team at one point. This would ensure the large patches of water get some use and would include bridges, boats, aquatic monsters, floating platforms (basically pontoon bridges you can build on), oil patches out on the water, and maybe new resources.
Dead Settlement. Houses, mutated villagers, and machines based around survival rather than manufacture.
Caves Could literally just be an opening in the ground. May spawn flying monsters that only attack at night. Would be blocked with explosives, which would give the base item a use outside crafting (say as a time bomb).
Satellite Relay Station. A small station in the wilderness that would give you field of view if activated and powered.
What do you all think?
