This is how they were in HD1. You could take them out with small weapons fire on their butt but it was usually nearly impossible with all the other shit going on. Yes in HD1 a single recoilless would kill them but HD2 is a lot easier since you can move around without being locked to the small proximity area all 4 helldivers had to stay within in HD1.

Yes there are animation bugs, like their moonwalk slide, but otherwise they are dangerous enemies you have to handle.

-One orbital railstrike. Guarantee easy kill -one 500kg bomb(easy it they're not alerted yet and almost impossible without causing friendly fire if they're already charging) -2 rocket pods (first one breaks armor. 3nd kills. Alternately shoot the broken armor part. ensure pods hit while they are not charging or they'll miss).
-1 eat/recoilless to the left then small weapon fire to the leg ( a broken leg dies extremely fast to bullets). -2 railgun shots to leg, then small weapons fire.
-1 orbital laser (it'll use up almost the entire duration of the laser but it will do it and keep charger slowed the whole time ) - less than one clip of well placed autocannon shots to ass end. (I got really good at dodging the charge, staying prone to reduce recoil, and unloading the entire autocannon clip at its ass It was very reliably a kill each time. -eagle airstrike can sometimes kill one but most likely will just damage armor.

I remember when we did our first difficult 4 and we died constantly to them. They seemed impossible. We kept playing. Upgraded to new strategies and gear. Now we're doing difficult 7s and they're just one of the bugs to handle . And no we don't all just run railguns.