If you mean those shields in Lana Sewer, they're not invincible. But looks like they have much more armor now so you need to kill shamans all the time. Otherwise they'll be able to heal shields to full hp. We killed them a couple of times on brutal using gas grenades + grenade launchers

I'm not stupid, we passed this mission before both with and without killing the healers, closing the doors, not doing it etc. This time the healers weren't even around, but we spent 15 minutes non-stop shooting these things in the backs. Twice.

The fact that it happened twice is even more interesting. Did you also read the Tears for Tarnor part of the post?

Is it happening for you all the time?

https://www.youtube.com/watch?v=Kh46ectJ8XY

Here's clip from yesterday. I also thought they were invincible but we finally killed them. There's nothing about increasing their armor in changelog tho so you may be right that they're bugged.

About immortal drones, it's an old bug. It also happens in vanilla Alien Swarm. Can happen on every map. You can't kill them with chainsaw or bullets, only with explosions. They can also die from ECA while hitting you

We gonna test it today again, but we spent a few packs of freezing nades, hitting them directly in the back. I wasted 5 full packs of autogun ammo to them, take a note that it was on normal (doing some achievement stuff). Not to mention dudes who played with me at the time and had Vindicators, PDWs.

Sounds too much for a simple armor update.

It's pretty inconsistent for me as well. I remember the first few attempts I made at that level left all four marines completely out of ammo with only one shieldbug dead (normal difficulty), and that includes the weapons scattered around inside the "arena". Definitely much more than the average shieldbug can take.

I've found that getting them to walk over an incideniary mine before hitting them with a freeze grenade is a pretty reliable approach. The continuous damage from the wall of fire combined with some grenades to the back has never failed yet to take them out quickly for me.

The invicible drones, on the other hand, are indeed very annoying.

I've got somewhat around 400 hours with the original game and another account combined, but I haven't encountered these invincible drones before (can't recall running into them before at least). The shield bugs were consistent across 2 runs, so we'll probably put some time to testing.

Ok I did some testing and seems like it's not possible anymore to kill them without gas grenades (at least on Brutal). I just realized those gas nades made 80% of work. Their damage is stacking so if you throw 10 of them to the same place, they'll deal the highest DPS from all weapons in game. This damage is high enough to instant kill every marine who'll touch it. For me it looks like every kind of damage is dealing 1 to those shields. So yeah, something is wrong with them for sure.

I had those immortal drones pretty often on many maps. But maybe it's because I have over 5 000 hours in both Alien Swarm and AS:RD together

Your post made me curious, so I tried the level again on brutal and confirmed that my usual strategy still works just fine, no gas grenades needed: throw down some incendiary mines, freeze the shieldbugs while they're standing over top of them, and then spam the grenade launcher. Took only a few seconds, although I did seal off all of the tunnels first.

I can't really blame anyone for wondering if it's a bug, though. I remember taking a chainsaw to them as Vegas once on normal difficulty and being baffled by how long they were holding on.

I just killed both shields with chainsaw and without gas nades on brutal. So everything seems ok

I tried multiple times with gas nades, with gl only and with chainsaw. Everything works just fine as long as there's no shamans around

nothing is fine there. sometimes they are bugged sometimes killable. even if shamans not coming.
they die in 25 secounds sometimes or never with same strategy and same amount of shaman getting to them.

I guess it's feasible that they could occasionally suffer from the same (or similar) issue that causes invicible drones from time to time, but I've personally never experienced anything of the sort. The only time I've ever had trouble was the very first time I attempted the level and expected regular-strength shieldbugs instead of the hardier ones presented.

The suggestion to replace the bugs with a single queen (or at least to give them a health bar or something) is not a bad one in my mind. Anything that indicates to first-timers that these are not regular shieldbugs would be a nice addition, and a health indicator would make identifying any invicibility issues much easier.

They can die, just the yellow one has 3000 extra health and the red has 4000 extra health, and all those shamans can top them up to full health in just moments, resetting all your progress.

I think a viable method of dealing with these as one person is vegas with a chainsaw, cryo sentry, and power fist. keep the shield bugs frozen and just carve them apart with the chainsaw, have an officer use incendiary mines at the north and south gates to keep shamans out, that or use tesla traps.

JUST DON'T LET THE SHAMANS GET CLOSE!

Yeah, killing them on "level one double hordes" on brutal was very hard, but if it is doable with only level one gear, it should be much easier with other weapons. In later tries we had no issue killing them, but surviving the rest of the mission. It is only matter of cooperation.

lul
how should it be easier as imploding them with like over 20 mines? nothing does this instant damage. 1shaman and you start from the scratch with other gear

I just had to deal with them. emptied everything we had. nothing even slowed them down. we dropped mines emptied clips and clips. blew barrels on them. after three tries we gave up.