Another tactical guide - hints for nightmare.

[LbISS]

I have finished the final achievement of the game. Before moving to something else I want to share some tips from my experience, cause some of the are counterintuitive. Hope it will help at least one person.
I will not talk about first 3 difficulties cause them are for babies and could be done with almost any tactics. All mentioned are more related to the expert and nightmare difficulties, cause there you will need some tactics.

So, my thoughts:

What do we need for "expert" levels?

Small dictionary
stormtrooper = rifleman,
tactical squad = freeze,
light energy squad = laser,
heavy energy squad = plasma.

Unit type

Shotgun - I have tried it a dozen of time and imho it's useless. It could help only on rare levels with narrow corridors and conveniently placed slots. But stormtroopers will do better.
Plasma is useless too - DPS is just too low, considering it taking space of 4 troops.
Rockets - could be used sometimes, high AoE and damage to HP. But in the end, it's still more reliable to get 4 small troops - more consistent DPS.

So, in the end it's leaving 4 troop types for us: Automatic rifle, Freeze, Laser, and Sniper.
Freeze is mandatory. You could forget about flamethrower from the start, cause it "cancels" freeze and freeze is OP. Increasing 10x time spent under the fire of your troopers is far more useful than just adding a little bit of DMG.
Sniper - is terribly useful. It has tremendous damage for the health but also could do decent against armored enemies on the first waves. Also, it's range allowing to hit all the map, which gives you possibility to prevent accident escaping of enemies last second by manually targeting them.
Laser is one of the core units. First of all, it is replenishing ammo, which could be useful if you will forget to call drones. It will shoot no matter what. These few seconds while you will find out problem and will call the drones will save you. Second, it's the mandatory weapon against armored units - no one could remove armor faster. Third - it has huge range, good weapon speed and some splash on top, which allowing him to decently deal with high-health monsters too.
Automatic rifles have a few purposes too. Together with the sniper it's the main damage dealer on the monster’s health. And, if put in strategical location - it's fairly good at throwing monsters back with the grenades.

Upgrades

Everyone should be upgraded, EXCEPT:
Shotgun- for shotgun you should skip the perk which increasing spread. Fully upgraded it is taking shotgun DPS to the zero leaving it as a niche weapon for specific narrow corridor cases. Shotgun in general is not the best weapon, but that upgrade makes it completely worthless. You could skip it completely OR just upgrade two times to unlock further perks.
Laser- skip last perk which makes enemies caught in fire. It's cancelling the freeze - and the freeze is our friend, remember?

Loadout

On "tactical troops" you need to have two weapons - the cheapest and the most expensive freezers.
For the other three you will need three weapons:

1. low-cost one (something like 3-4th from the start),
   
2. 2nd from the top - cause for some level you will not have enough to buy the top one from the start, but you will need the soldier on the start to be able to pass level, so you will buy cheap one and then upgrade. I'll tell why you need 2nd from the top weapon later, in the "nightmare" section. Sometimes it could be swapped with some medium weapon, just if you need two-step upgrade during level.
   
3. and the top one.

Of course, all weapons should be legendary, and max upgraded.
And you should have enough of every active of ability - 150+ mines, 100+ dynamite, 100+ drones - just for the case. Cause it's too upsetting to miss 1 caterpillar at the end of the level when you don't have mine.

What to do on the levels

You will start usually with 200-400 coins. Typical solution when you have enough money: place freeze + laser + rifleman. It will be enough to deal with most of the monsters. If not - then you can try freeze + laser or freeze + rifleman, depending on the type of enemies you have on the level. Then you quite quickly will have a stable flow of money and then you can get additional troops. If you are combining these 4 soldiers and upgrading them in time - you shouldn't have too many difficulties up to level 36. And on 36+ you will need to use a little bit more active abilities or just think more about location where to place units - but I'm sure, at this point you will figure it out, it's not THAT difficult on "expert".

And what about nightmare difficulty?

The mentioned above will carry you fine up to level 15-16 of nightmare. Then it's starting to get really hardcore.

1. You will need to place all the troops precisely on the specific strategic area for each soldier - considering combination of troops you can afford and the map of the level. It's more or less unique to each level, so you will need to find this combination which will carry you at least a few waves to get enough money for further actions.
   
2. Most probably, you will not have money to spend on ammo at the start of level. So, ammo drones - your best friend. Disable "auto buy" for ammo and use drones for replenishing.
   
3. For that reason, rifleman is not the best unit to start in many levels, cause their rate dmg/money is quite low - it has high rate of fire for the medium price of ammo.
   
4. Manual targeting - is your friend. Default shoot priorities for the troops is quite ♥♥♥♥♥♥ and if you will not target manually, you most probably loose. Some enemies will be left with 1% HP, laser guys will target HP enemies instead of armored ones, and then armored enemies will pass to the riflemen which will not kill them in time, you will not have enough money because you will have dozens of 10% Hp enemies on the screen, etc... It will fail you many times.

Start of any level on nightmare difficulty - is high APM time, comparing to other difficulties. You need to place troops, reload them in time with drones, manually targeting all of the enemies, place mines, use active "laser beam for the cosmos", upgrade troops, etc. So be prepared.

Usual start is to get the cheapest freezer and the most expensive that you can afford sniper. You need to manually target enemies, in case it's just HP - target the ones, which sniper can kill before they will leave his area. In case of armored enemies - kill a few first ones to afford rifleman in the back of the sniper and then only destroy armor on them and then retarget - rifleman will get care of them.
And then we're getting to the 2nd step - and it's the most difficult thing in the game. Because, as a said, you will need to find for each level specific step which will carry you further. Consider next things:

• It's quite urgent to upgrade rifleman to the max as soon as possible - otherwise you will need to call ammo drones every 10 seconds. So, if sniper is doing fine with the armor - do it.
  
• You will need the 2nd freezer right after the range of the first one - it'll allow less manual targeting, because it'll "catch" monsters which have passed the first freeze and also increase effective damage for stormtrooper. And you will need APM for all other stuff...
  
• If you have a lot of armored enemies - most probably you will need the 2nd sniper on a distance further on the track and then trying to get a laser squad at the front as soon as possible to reduce armor. Also, if you have a few armored waves one after each other - probably you will have to use activated laser beam.

You need to go to 2-3 freezes, 1-2 snipers, 1-2 upgraded laser and 1-2 stormtrooper asap. That's minimum sustainable configuration. But it's still not the end as nightmare is keep going, you will need to work hard almost through all level if you want to get perfect result. Unfortunately, I've not written down positions and order of placing stuff for all levels, so you will need to improvise. A few additional considerations:

• Freeze should be placed along all track, it's helping a lot. Where the range of the one is ending in a few "meters" should start the next one. You may allow some gap between their ranges cause freezing effect have rather long time and the monster will walk a little bit further in a freezed state.
  
• Separate every track in two "parts" - first one to get off "armor" with laser guys, the second more focused on HP with assault rifles. Manual target on the first monsters with armor without killing them, so the 2nd part will be able to deal with them with no issues.
  
• Target small bugs and caterpillars asap. It'll not take too much time to kill them, but they easily can slip, and they are going in a huge numbers, each one will take the same 1 HP from the base as large monster.
  
• For the same reason always place a dozen of mines at the end of each track. Just as a precaution.
  
• There are an aliens which looks like giant caterpillars with turtle shells. If you're not going for perfect run, sometimes it's better to not target it, because it'll damage base for 1 HP, but if you will destroy "shell" - it'll spawn a lot of small insectoids, which will take more HP from the base.
  
• Do not place the same trooper near each other. After killing an enemy, the troops have time required for "retargeting" to the next target. If the same soldiers placed together - they will kill the same monster twice as fast, and both will require retargeting. It will increase their time "doing nothing". So spread them as much as you can.
  
• And here can help 2-nd weapon. Weapons have different range, retargeting time as well as different "reload" time, so if you need to place two units of the same kind together - give one of them not the best weapon, but 2nd to best. They will shoot in different cadence and most probably on different enemies (due to range), so it's far more effective, even one has inferior weapon.
  
• Do not try to always maximize area, which soldier is covering. Each troop should do own task on specific area of the track. The laser should remove armor and do not need to shoot on monsters without armor. Assault rifles should not shoot on armored enemies. If everyone is covering the same area - when they will target not-effective targets and waste ammo and will have reduced DPS. Also, again, they will shoot the same enemies and will have additional "retargeting time" after killing them.
  
• Also consider manual targeting when placing units. You can place only one target at a time, so you need to consider areas of troops when you're placing target. Place it near the needed troops - they will be able to shoot and for all others the target ideally should be out of range, so they will still work on autotargets. Yes, we're struggling a lot with the targeting system in the game. But that's how it is.

Making use of that I can pass every hardcore mission in the game. Not all of them are perfect (and I will not do that, too lazy), but I'm still trying to achieve perfect run at least for level 40. I've spent a few dozens of tries on that and in the end the closest run for now is 38/40. I think that's the last thing I want to do before deleting game.

[insect]

Much Thanks