Well after a good 8 hours I can say that map design is a flawed point in the game. Everything is either a grid based level in a star ship, or a slightly less grid-based level on a floating sea platform, a glacier, or something else. There's no verticality to maps at all. You can even clearly see how the tiles are assembled in the mission preview windows.
What saves this from being a total disaster is that the game can be tough, and you can essentially choose how tough you want it to be by the challenge rating of the mission you pick. So this is less like Diablo where you roll in and melt the faces of 120 guys in a pack swarm all at once. You have to tread carefully because they start throwing packs with 2 to 3 elites in them at you, and between them shooting you and pounding on you, the damage and suppression (basically a bar that goes down as you take damage and when it gets too low you start getting stunned, knocked down or slowed) from the lesser swarm enemies starts to pile up very fast. And because your health and gear items are on a cooldown, often you have to retreat or at least seek some cover to buy yourself a little time.
So maps kind of suck but the combat difficulty and finesse seem to be there. You have to play slightly tactically to disassemble these hordes in good order, and that often intersects with both your class and your gear choices. Nothing will ever be "unbeatable" based on the things you've chosen, but it can definitely be harder.
Best moment so far: went in to a mission to exterminate some guardsmen who had been slated to get mind-wiped after their mission but the purge had some how missed them. I'm running around gunning them down, all is great.....when I find the last group of enemies in the level is supported by a FUCKING TANK. And here I am with a Chainsword and Shield, an Autogun and a Personal Void Shield. It took a lot of running circles around the tank carving it up with my chain sword. Of course you'd never kill a tank with a man-sized chainsword or an autogun but game needs must I suppose. For this reason I switched my loadout to a Power Sword and Shield and a Plasma Gun to deal with armored opponents. I'm not a fan of how the plasma gun shoots or sounds but it gets the job done.
So yeah. Combat's difficulty and how it starts getting technical with gameplay as soon as the tutorial levels are over kind of save it from its own design. If you had to worry less about enemies, you'd have more time to grouse about the level design. But fights can be challenging enough that levels, eventually, do an adequate job. I just wish they were more fun to explore, the only things they offer you outside of the mission objectives are consumable resupply boxes and the occasional chest with random loot, which you honestly don't need because the game SHOWERS you in loot after every mission, 90% of which you won't use. There is also the occasional set of traps (explosives, alarms that spawn enemies, locked doors and poison gas) that break up the repetitiveness of hunting down enemies. It's just not enough to make these levels feel alive though. There need to be patrols of enemies. Tile set rooms need to have SOMETHING going on for them other than a group of enemies, some cover, and maybe a resupply chest or two. If levels were great, I'd call the game great. Right now I can only call it good though, because of this single element.
But yeah, combat does require a little bit of brain power. Everything needs to die but the order in which they die determines how hard it's going to be. Do you:
-Shoot or explode all the weaker guys? They don't do much damage or suppression, but as a whole they both can tip a fight in the enemies favor if you leave them alone. Guys with flamethrowers especially will shred your suppression quickly and leave you very vulnerable.
-Kill the elites? Big guys with big guns and tons of HP take a while to kill, but their damage and suppression cannot be ignored for long. A single one of them isn't a match for a player, but an elite backed up by plenty of lesser units is.
-Kill the leader? Leaders may not hit as hard as elites, but they have tons of HP and buff all the enemies around them. While you'd usually want to kill them first, the buffs they add to all the enemies around them make their damage much, much more dangerous, to the point you don't have the luxury of wailing on the leader while their entire troop shoots you in the back. Or they'll drop in or summon support units.
-Destroy their support vehicles and turrets? Leaders regularly drop tarantula support turrets in to the fight, which can be the straw that breaks the camel's back. While they aren't super damaging or super tough, they're armored and that firepower can sometimes be just enough to push you over the edge.
So for me, despite really hating the plasma gun, it's an effective weapon at singling out guys to shoot from range. Where it'd be suicide to charge in to melee, the plasma gun can help you whittle down a pack to managable levels.
On top of all this, enemies often regenerate health very fast. It's not clear if this is just elites and leaders, daemons or most units, but you don't have the luxury of sniping down guys' health and running away, they will regen that lost health after a few seconds. So you have to keep the pressure on in combat when it comes to tougher targets, and that can occasionally feel too hard, especially when you've already blown through all your healing and supply pickups.
Also I'm not sure I like the active abilities being purely tied to gear. I like unlocking new skills and abilities and modifiers for how those skills and abilities work in these types of games (and picking and choosing to make my own build) far more so than unlocking e.g. lots of +2% fire damage upgrades, but what I've seen this looks to be more of the latter than the former. Seems like you'd be choosing which weapon(s) to use fairly early on and that's your skills for the rest of the game. I dunno, maybe there's more build stuff that I've missed/not seen.
I'm not 100% clear on which it is yet either. I think in a way, weapons stand in for skills. You unlock more and more of the 40k armory as you level up, so every couple of games you're like "Oh sweet, that weapon is in. I gotta try that!"
For example, I got a plasma pistol and was like "I gotta try doing a chainsword in one hand and a plasma pistol in the other." Turns out that most but not all weapons have 4 abilities. If you dual wield two weapons that each has 4 abilities, you get the first two from each. So I ended up with a build that had a "channeled" melee attack (which is what chainswords do, it's called eviscerate, it's awesome), a crowd cleaving strike, a single shot from the plasma pistol or a slightly harder hitting single shot. I ended up scraping that combo because the plasma pistol just can't compare in usefulness to the suppression shield, but it's fun to mix and match stuff like you're building your own table top hero unit.
So far the most satisfying weapon I've used in game is the humble Autogun. While it's probably the least appreciated or iconic weapon in 40k, in this it sounds GREAT, does really good damage and has multiple firing modes, all of which are situationally useful. Unfortunately the gun lacks any real armor piercing damage, which in 40k is basically a must.
Lastly, I think this is a decent channel for gameplay vids, the video quality seems good. The dude looks like he has played a ton of it. I make no claims as to his quality as a youtuber though, never heard of him before:
https://www.youtube.com/watch?v=oVu0i8GXSTU&list=PLy5KHwY-7WyZ_mBF569Wyn_tzAYj7cdSO