TL;DR
Change pollution behavior completely by adding passive scouting parties that try to find the center of your pollution cloud if it's severe enough, and leave behind a trail to warn you that an attack is coming and from which direction.Change evolution scaling such that earlier on (small->big biters) pollution matters more, and later (behemoths) killing map-generated enemy nests matters a lot more (showing you are expanding your base).
And some balance changes as well.
The suggestion
Create non-attacking scouting parties roaming around the map even without pollution. They may cross through your base without hurting structures and are near harmless by themselves, but if they go through a tile with high enough pollution (higher than 30 to 60, where 60 is around 8-10 mining drills without efficiency), they will look agitated and start running around, checking neighboring chunks until they find the one with the highest value before going back to their base(s) while leaving behind a colored pheromone cloud that indicates the attack path they will take. You can show this as warning on the hud (like when taking damage) if you have vision of the area.The pheromone trail does not necessarily have to be a straight line to their base, and can involve multiple bases (2 bases creating a Y-shaped trail, merging 2 attacks into 1 location).
Pheromone trails dissipate slowly if the pollution level is under a certain amount, forcing them to re-establish new ones.
There may be multiple pheromone trails (multiple paths they can take to send attacks) connected to the same nest if the pollution is so high that the trails do not dissipate and more scouting parties from that nest established another.
Each pheromone trail will make a nest produce more enemies, but a diminishing rate (e.g. 1 trail = 0.5 wave/min, 2 trails = 0.8 wave/min, 3 trails = 1 wave/min etc)
If you harm any scouting party, they attempt to flee back to their base while creating the trail to their base.
If you kill enough scouting parties, future scouting parties will start wandering around with the stronger hostile biters as defense -these guards get increasingly stronger with amount of scouting parties that didn't come back to guarantee the scouting party finds the center of the pollution (or something that hurts them).
If you want to play pacifist, you can let scouting parties roam through your base unharmed, or build a very big wall that biters will ignore -as long as they don't smell any pollution outside of the walls. A wall would also prevent expansions without conflict, thus still encouraging nuance even when playing pacifist by claiming territory before they do.
Of course, pollution should be adjusted accordingly.
If enough enemies/nests are harmed outside of scouting party triggered attacks, all biter behavior becomes completely hostile for a long time and scouting parties are replaced by roaming attack parties.
If the same level of high pollution reaches a nest directly, the nest does not produce more enemies or absorb pollution -instead, more scouting parties will naturally cross the cloud and generate more attacks as a result. These additional scouting parties may come from nests which are significantly further away.
Biter nests will still want to expand as usual, but will not be hostile when doing so unless many scouting parties were harmed.
Evolution scaling is also flawed: earlier on, you should be "on a timer" such that taking too long or making a ton of pollution causes more biters to show up. However, after big biters, if you just AFK for a while you will progress evolution a TON even without polluting, and the timer does not feel exciting at all as it takes many hours to reach behemoths, and it is not exciting.
Behemoths should be reached mostly if you destroy many map-generated nests, showing you are expanding. I say map-generated, because clearing out -their- expansion does not really count as expanding yourself.
Of course, the other factors- time and pollution- should still play a role. Especially pollution.
Why?
It sucks that the fighting in the game is limited to one of the following:- Kill all nests within pollution cloud and barely worry about it again
- (on higher difficulty settings) Generate pollution by fighting enemies too much, creating a death spiral
- Make a big wall everywhere around the base to defend against every attack
Knowing where an attack comes from would make combat significantly more strategic beyond the choices of "defend everything or kill them before they come".
Defense balance
Here are the pros/cons of each defense type:A) Ammo cost: The defense does not need to be supplied with ammo / the ammo is infinitely renewable with ease
B) Time cost: The defense takes little time for the player to set up
C) Resource cost: The defense is cheap
D) Upgradability: The defense can be upgraded into late game with only minor modifications
I will be using colors: (X) for great, (X) for average, (X) for bad, (X) for non-applicable
The options for defense before going to other planets are as follows:
01) Radars + offense
(A) Very little ammo
(B) Shorter than setting up a full wall
(C) Ammo/radar cost is small
(D) Really bad late game
Feels very balanced.
02) Clear all nests on the map without activating new chunks
(A) Small cost
(B) Short for wiping out all enemies
(C) Cheap if careful not to activate many chunks
(D) Same as playing on peaceful mode until you expand
This one is pretty busted and feels like a bug, so should probably be fixed by having chunks right next to fog of war be considered for nest expansion candidates.
03) Landmines and roboports
(A) N/A
(B) The fastest of all
(C) Moderate cost
(D) Horrible at scaling up
A horrible option outside of speedrunning, in my opinion.
With the suggestion however, it would be extremely good as you would know the path of the enemies. Not the most automated, but still very good if trails last a while.
04) Gun turrets
(A) Extremely high ammo cost when automated
(B) Incredibly large amount of time to automate (power poles + inserters + belt - using burner inserters means losing on belt throughput which can matter later on)
(C) Cheap to produce
(D) Horrible at scaling up and incredibly annoying to switch their ammo type when upgrading
Gun turrets, when used manually as offense, are in a great balance spot.
But when used as an actual defense with belt-fed ammo, they are awful unless you know exactly where they will attack.
The biggest reason they are used is because they are often the only option early on.
A big issue with using gun turrets as a defense is that their ammo produces a lot of pollution, which triggers more attacks, which uses more ammo so more pollution, though this suggestion would fix that.
I still suggest reducing the flat physical resistance on medium, big and behemoth biters while increasing the % physical resistance as evolution increases would help to allow an automated gun turret setup to work.
Note that currently, red ammo deals 8 damage without upgrades. Medium biters have 4/10% resistance, and big biters have 8/10% resistance - rendering even red ammo pathetic against big biters even with the first few upgrades.
05) Laser turrets
(A) No ammo cost
(B) Very short - power poles and turrets
(C) Very expensive, both in power draw and resource cost
(D) Scales up very well with investment
Expensive but good.
06) Flamethrower turrets
(A) Insignificant ammo cost, and renewable ammo, minor amount of repair packs
(B) Somewhat short - pipes and walls, roboport for the wall repair later
(C) Extremely cheap
(D) Scales up insanely well into late game with 0 investment
Absolutely busted. Insanely OP. You don't need to nerf the amount of total damage it does, but how fast it deals that burn damage (DPS) is too much, you should need significantly more of them.
The oil consumption is also absolutely laughable, especially considering it is an infinite resource on Nauvis, it should be nerfed as well.
There are also the turrets you get from other planets, of course, but I won't go into detail of those.
