A lot of textures are old and outdated, such as turrets, electric mining drill, trains and train stops, portable fusion reactors, etc. Maybe just look through all the textures and see if they look bad or outdated. I also thing the stone furnace should get a new look.
The cluster grenade research icon looks lazy compared to everything else, and the cluster grenade itself has a bit of a lazy icon, (different hue of grenade).
Underground pipes and belts should have a very high length, and they just take up belts/pipes in your inventory depending on the length of the belt/pipe. Underground belts use 5 belts in crafting, but what if you make the length of it 2? where did the other belts go?
Also, maybe when an item is moved by an inserter, it rotates as it moves, or maybe it is in a random orientation when its on the belt, to make it look more realistic.
Maybe trains could have speed limits in signal blocks, and using that, a train would take the faster speed limit route. Because maybe it could be a 'train highway' and there is a slow lane, and fast lane.
I know there are shadows, but they are not relative to the sun, because they are just fixed in one place. I think they should move and stuff.
the best idea i think:
Weather!
rain that makes the ground wet, thunder, fog, cloud shadows etc. But if this were to be implemented into the game, it would have to be really good and realistic. Water dripping from machines, and running down stuff
Please consider these ideas it would be amazing to see this happen soon!
