Factorio Forums

TL;DR : Make the biters into more of a civilization with the endgame being the conquering of that civilization.

Explanation:
I've read the sticky posts and they say keep it short, but I had this idea kind of late at night so being concise was difficult. The general theme of the idea is that some mechanics of the game can be improved by making the biters into a civilization.

The mechanics that can be improved:
Evolution factor - currently when you attack the biters they get stronger, and when you pollute more they get stronger. Instead, the biters could send reinforcements and better units and technology from their main empire to respond to the threat. Pollution would aggravate them more, and attacking them would make them send more reinforcements. This would give a logical reason for why the biters are getting stronger and more powerful, other than "they need to evolve to the threat".

Alien Technology - when you make the science packs (SPs), the "science pack 4" or the "alien technology" is quite disappointing. I don't think a single person would think that SP4 is actually more difficult and more interesting than the SP3. Blues or SP3s are always the bottleneck of research. This can be solved by having the aliens make specialized outposts with distinct alien technology. Faster hoverblades, faster treads, better solar panels, better batteries and accumulators, better fire rate and robot capacity, better roads, attack drones, etc. General improvements and technology can be stolen from the aliens and used with your own technology. This would actually feel like you're using "alien technology" instead of having some random purple goop that you turn into improvement somehow.

Lategame - at the beginning of the game, the biters are pretty terrifying. By having them respond to threat and having them have outposts and an actual civilization, they can be more threatening to the player later on in the game. The player would also not have very good solar panels until he steals it from the biters, so they would continue to get aggravated by the player's factory. This response mechanism and the biter's centralization of technology creates need to attack the biters. This creates need to explore and conquer. This creates need to engage in the biters, because currently they're little more than a nuisance.

The Alien Gas - make the aliens have a special resource, like a gas. Every town and outpost and settlement the aliens make is centred on a well of this gas. A large component of alien innovation and technology is based on this gas. The presence of distinct towns with actual technology that you can steal and also the introduction of this gas would give incentive for the player to think about their environment. This resource and the distinct alien technology would give the player incentive to think of strategies and plan for which outposts he's going to attack.

Endgame - the point of this game is making a factory. It's called Factorio, so that's what I've assumed. I think letting the player keep building the factory with the tech they scavenged while attacking the aliens is the best course of action.

While ye olde Biters and their humble contribution to purple science could be tweaked a bit, I think other worthy idea would be adding more intelligent natives to a planet.

Kind of alien tribes that would live peacefully, aligned with biters and nature.

But then our pollution destroys their fields and corrodes their monuments, our brute escapades for resources enrage biters and pose a threat to civilized villages and cities.
And as they try to fight back, their bows and spears are nothing for our mighty gatling turrets and tanks, so to win, they would have to create their own science facilities, trying to outrun us in arms race, to either defeat us, or to carve themselves new home among lesser tribes. They would start their own wars, so there would be no free space to take effortlessly for expansion. They would create their own pollution, that would throw thousands of biters in every direction, with our factory being the most abominable beacon of foulness, bringing rage of countless nests upon us. Those alien kingdoms and empires would start using resources we crave the most, resulting in brutal wars over richest mining spots, where no one spares any mercy.

Though in this case, fellow spess compatriots migrating from other worlds to man our defenses and to enlist into our infantry brigades and tank divisions would be necessary, to upkeep with greatly increased stress exerted on our defenses of main base, or outer keeps and outposts.