Factorio Forums

Suggestion
+ Enemy Composition Variety and Randomization
+ Enemy Type: Evolves very slowly, assaults extremely frequently, weak overall
+ Enemy Type: Evolves very slowly, assaults extremely rarely, but is incredibly deadly from the beginning
+ Enemy Type: Very strong, attacks extremely frequently, but in extremely limited numbers
+ Enemy Type: Varieties that disregards pollution as motivation for attack (they're just jerks that attack for no reason)
+ Enemy Type: Exceptional Resilience to popular weapon types (e.g. flamethrowers)
+ Enemy Type: Exceptionally Resilient, Slow, Exceptional Damage (for walls), but does not respond to any attacks and singlemindedly heads for offending pollutor structure
+ Enemy Type: Very Low Damage, Small Numbers, Quit attacking offending structure after a short period, but becomes very aggressive and destructive if attacked.

Reasoning:
+ Common strategy is "keep your pollution down until your technology vastly outclasses the enemies capabilities" which is not particularly exciting (essentially playing with no enemies)
+ Creates a more dynamic game style: each game forces you to constantly reassess the proper balance of your non-military research with military research. Also forces you to assess priority in weapon sub-types based on threats encountered.
+ Turret placement must be planned carefully based on enemy composition and consequences (especially against the last listed enemy type above, for example)

Bear in mind Factorio is at the core a game where you build your factory. Combat is just an incentive to build more and drain some resource.
What you ask would be better covered with mods. Fortunately, there are already tons of mods that make the enemies "more interesting".

Exactly. If I wanted a combat experience, I would play a combat strategy game.
This game is at core, about building an automated factory.
Yet, there are enemies in the game that grow stronger, attack, and military technology.
Why?

To provide another dimension of gameplay.
You must balance military science, which is normally low priority, against other science that directly affects your progress towards the rocket.
Furthermore, the option of "death world" is included in the game, for those who want that extra dimension to have a greater impact on their gameplay.

Thus, what I propose(d) is NOT an inclusion of an overarching combat system, but simple variance and randomization.
Not even adding new assets to the game or units; simply offering a greater range of behavior for existing units.

Currently, dealing with enemies is no more complicated than "build turrets and walls and ignore them".
I see remarks on the forums that most people play with enemies off, because they don't add any challenge, just tediousness.

I'm not asking for a mod with new enemy types. I'm asking for an easy inclusion addition to the vanilla game that I feel belongs there and takes a minimal amount of effort to implement.

There could be also a count of damages done by each ennemy type in the last attacks, used as a modifier for the probability of this type to be spawned for the nexta attack, increasing the proba for the bests and thus their number in the next swarm. The size of the swarms could be modfied too by the same way : one swarm àf 30 or two swarms of 15? And so on. Ok all my suggestions are AI-related, but this game is heavily AI-related: it's clearly Turing-complete, even without explicit signal processing: even without it one can make an autoregulating factory.