Now, you'd be looking for an expert's opinion on how to play it out. Instead, take a novice's experience from how you exactly not screw up or trip over during the hardest of missions. No worries, this will be a pretty useful guide, based on my luck and bad decisions.
We're going to talk about accidental griftings, becoming lost on objectives, having mission awareness, always find something to do, pick useful equipments, and I repeat, always pick the right ordinance for the right fights. People even skip out on mission briefings, and forgetting to pick boosters. You could even be diving with a full assault build in a defense mission.
You know, the fight for Super Earth is never an easy trait, especially with so many random phenomenons happening around the galaxy. But fear not, for the might of our military were able to provide bonus strikes and orbitals. Trust me, you'll need em.
Since the latest patch, it's gotten trickier to the point. It's no longer about massive enemy fleets, but fog on the map, serious weather storms, tremors which are useful since even enemies couldn't move, and tricky communications creating delays for mission objectives and extractions. Yes, I'm not the best HD2 player, at this stage now, neither of us will be. Hopefully this will a refresher too.
What it boils down to is a few simple rules: Engage, Observe, Collect, and Signal. You're going to be dealing with various problems, some players will not follow up requests like more ammos, retrieve samples, properly align radio towers, do mission objectives, and there's plain grifting.
I remember times when I found a bay door with credits, and other important items behind them, and all they got busy with was fighting the onslaught while there were periods of calm. Like, forty minutes of mission time, and no one bothers to open a door for 30 seconds of their life. I'm guessing with how drastically difficult the conditions are, players are less inclined.
My suggestion would be to find a buddy willing to help you farm, I cannot stress just how important collecting samples are. You're missing out on ship modules. We're talking about increased firepower for Orbital, and Eagle strikes, reduced cooldowns on stratagems deployments, hell your deployed sentries take less damage, well on useful occasions. Also, for the experienced players, please even if you've unlocked everything, least help out a little or give time before calling extraction.
I've also noticed certain people so easily getting caught when bombardments happen, I even got cursed by one player. Of course, partially his fault for not seeing it. Nonetheless, even one guy failed to extract because he ran straight towards them. You can use the ping system, but I wish there was one specific to signal a strike happening. That would do wonders.
Do not fret, you screw up, least apologize, we all make mistakes, it's hard not to be stupid when everything around you is absolute chaos. Especially in the later difficulties, which you shouldn't touch even if you unlock till you're at least a few levels experienced.
If you've gotten to the point of playing in the harder skirmishes, welcome to the real fight. I know I said dropping bombings and strikes are hard risks, the thing is, it's all about going crazy first, and then learning to manage it later. Take the risks, screw up, and learn.
Life's hard, we can't keep running around while everything is trying to kill us, and hey, if you're a slow on the deployment, just use this site to practice. There's even a mobile app for this too. Be smart about your environment as well, dud hellbombs, terrain is rough, so visual map it and find ways around, heck get a jetpack to fly off areas out of reach due to the dense water.
Since this game was purchased early Jan, I've seen been significant changes. This is the developers basically saying "yeah, we made weapons better, now we're going to punish you for enjoying them by making almost everything worse". Look at those flying Automatons.
I've seen grifting becoming the norm, but wasting reinforcement in the higher difficulty is an absolute no-no. I don't care if your account got carried, and you're still new, or you're just playing it cozy, I will report anyone that goes too far. Ok, maybe I need to chill. It even sucks going by myself, and trying to risk collecting stuff, almost before being killed and reinforced further from my equipment.
The smarter thing to do would be to split 2:2, do the side stuff and collect as much possible, before taking on main objectives, and then evac. Not many people do this, however.
If you're bad at dealing with rough situations, just always have a sentry around to distract them, and have heavy weaponry to take out high armored/shielded units. Sometimes dropping bombs just don't cut it with these guys, they move too much. Take my word for it, I've been on crazy goose chases, wasting precious time even running from tripods, tanks, titans, and so on.
Lastly, just play the game right, do much as you can, farm for requisitions (look at YT for tips), and get the best weaponry (again, YT for suggestions), as many as you can. We're going to need all the help. Don't let the heavies and vets carry the game. Read the mission briefings when joining in, and pick the right stuff. Happy Helldiving! Also, R.I.P. Angel's Venture.