City you should be getting past machine gun use.
Some of the modifiers can also drop stuff in at the kind of range they will get shots off so you should invest some thinking into defending your tower. Those walls will then also give you places to put your batteries etc.

Dear EndlessPlayer,

First off, awesome base! Your on the right track for sure. Ill try to answer your questions before any advice:

Originally posted by EndlessPlayer:

I wonder what is better for Operator, when he/she is on the field - Armor or Defence?

Armor and Defense are apples and oranges. Armor will be an actual amount that takes damage before your HP does. Defense reduces the amount of damage your armor or HP take when something attacks ya. Trying to maximize either one is a valid path to being strong.

Originally posted by EndlessPlayer:

I also use the trick with colums and generators to boost Core Outpost and learning that for each 100 Core Outpost I get additional space for container, but after reaching 1000 this stop growing.

Power Storage and Core Output are actually 2 different things. Your core output has 2 milestones really. The first is at 3000 and that is where your x-boost field will stop growing and you will get the max defense bonus for your character while your inside it. The second is at 10000, which is the point that your core output will no longer increase the amount of damage your Damage Amplifiers add to your turrents. Most pieces will add core output but only certain ones (battery pack, regular battery) will add to power storage.

Originally posted by EndlessPlayer:

I don't know, how yo use them, as trying to make auto-refilling autoloaders (ammo maker + conveyor + autoloader) don't work, knowing only that throwing things to container will still storage them, and only seeing this as for usefulness for conveyors.

Autoloaders can be tough to figure out. Too start tier 1 ammo makers and tier 1 autoloaders can be used together but they must be manually controlled to load ammo. e.g. place the autoloader with the grab claw side facing the ammo maker on the ground. Select ammo maker and make an ammo box, then select the autoloader and use its ability to take the ammo box from the ammo maker. To make the process automated you need a tier 2 Advanced Ammo Maker, some conveyors, and a tier 2 Advanced Autoloader. The Adv Automaker is mounted to a wall (fits utility wall or anything with a 4 point square pattern) and when turned on it will spit out and ammo box onto the conveyor once every minute for 150 mats. The conveyor will take the ammo box to the pickup point of Adv Autoloader where the autoloader will automatically pickup the ammo box to then load turrets.

Originally posted by EndlessPlayer:

From this, I want to know, how useful are other weapons like Cryo Turrets, Knight Hangars or XEN Turrets, as don't pay attention how each weapon is good do dealing agains hordes and they are often expensive and for Knights (or even guardians) I often found that they can't survive to long (I don't use knight even once, I don't know his usefulness).

Most of the late game stuff does have specific uses that you can use or not depending on how you like to play. Because of this, most of the rest of this will just be my own opinion.

- Cryo Turret: Will freeze enemy in a short range. Works best in conjunction with a pyro turret or machine gun turret. Since the range on the pyro and machine gun isnt that great the cryo turret will give these other turrets enough time to kill enemies. While the machine gun turret is viable by itself the range on the pyro turret is so bad that its only really useful when paired with this turret.

- Guardians: These are priceless for more difficult stages. Think of them as extra soliders defending your base. They can potrol an area or follow you for protection. Some like the pack mule will carry items for you or take them back to base while your exploring a map. The support guardian can repair things (turrets, walls, other guardiands, your own armor) and acts as a mobile autoloader with room to hold 4 ammo boxes. Reaserch the guadian fabricator and an advanced guardian fabricator so you can ride your guardians to victory!

- Knights: Super fun to jump in and use! They come in 3 flavors; Tier 1 is just the Knight. Straightforward, the knight can be reloaded with ammo boxes and if you jump out after deploying it , it will go into auto mode to attack targets around you. You can control this from command mode just like a guardian. In many cases however by the time you unlock the knight your own gun will probably do more damage.
Tier 2 Knight is the Vanguard, sporting more firepower than the knight, it can be put into a defensive mode where it is no longer able to move but acts as a twin mounted 105mm artillery. Is also reloaded with just ammo boxes instead of shells so can be very useful out in the field. This cataphract is considered the most powerful of the 3 with the best dps output.
Tier 3 Knight is the Ranger. This one shines in the department of mobility. Booster fuel is consumed much slower than any other knight making you able to move large distances quickly (even fly).

- Xen Turrets: Best turrets in the game (IMHO) due to being able to set them to a xen combo that you are using on one of your weapons! This makes them extremely versatile being able to do basically anything you could do with your weapon from shooting healing rings to firing gale tornadoes to wipe large lines of small enemies. Major down side to these turrets is that instead of costing a set amount to use, they cost a percentage of your overall material storage, which means that too many will tank your base storage abilities.

Gonna stop there because this is getting long, but if ya have anymore questions feel free to post again or DM me, as im always happy to help :)