Boltgun is probably my favorite single player FPS I've ever played.
When I ask myself why that is I can think of 3 reasons:
1. The amazing visuals and sound design (the gore, the guns, the way the guns make the gore, the different enemy types and they way you turn them into gore and the sounds they make...)
2. It feels great to play. You can zip around really fast and quickly switch between weapons to dispatch different foes.
3. The simplicity. Every mechanic in Boltgun is as simple as the next. It's straight forward, to the point and clean. The hardest decision you'll have to make is which weapon to upgrade every level.

Anyways, I'll get my few hangups out of the way.
1. Sometimes the levels can be bit confusing and you'll have no idea where to go or what to do next. For a game that asks you to hold W and go into flow state, wandering around for minutes on end figuring out where to go next on certain levels can be a bit of drag.
2. Some of the Secrets are behind secret doors which literally just look like plain wall. There's a bunch of these that are bullshit and in order to get all the achievements I had to use a guide.
3. I wish there was more. Not really a criticism but I loved the game so much that even after 2 playthroughs I felt I needed more so I went for a cleanup 3rd.

What else is there to say? The game absolutely rules. Possibly the most fun I've had per hour spent in years.
Not to mention it's fairly short--around 8 or 9 hours for a full playthrough.
I'd probably recommend this game to literally everyone and anyone who likes games. Sure, it's Warhammer 40k but your potentially lack of 40k knowledge wouldn't hurt a bit--knowing about 40k could only enhance the experience.

PLAY 40K BOLTGUN!
It's crackled. It's GOATed with the sauce. It's swagged out, it's epic, it fucks, it bangs and it rules.
The Emperor protects

My experience with Rogue Trader was... utterly transformative that I don't even know where to begin.
I'm a fairly fledgling 40K fan--I practically just started with Darktide when it released and have since played several games and watched countless Lore videos on Youtube. I hold the 40k universe in very high regard and for what it's worth, I think Owlcat does 40k justice with Rogue Trader. If it wasn't a 40k game I'm not sure I could've gotten past its myriad issue but alas, I triumphed.

It's difficult to quantify what I really liked about the game and a lot easier to talk about what drove me insane so let's get the hard part out of the way, first.

The Good: Like I said early, Rogue Trader does 40k very well for well for what it is. You get to amass an awesome retinue with a character from all your favorite factions: A tech priest, a Sister of Battle, an Inquisitor, an OP Navigator qt, a fricking Space Marine(!) an unsanctioned psyker (she's mid), an Aeldari ranger, a Druhkari Kabalite and you even get an old man and old woman (just because.)
I feel like this game is the epitome of Warhammer 40k fanservice, for better or for worse. The more you like 40k, the more I think you'll like this game.

On the other hand, I've heard some people say "Rogue Trader is a great place to get into the 40k universe!" and I couldn't disagree more.
It's time for....

The Bad: Now, I have to give credit where credit is due. Owlcat games is a fairly small and newer studio with only a handful of games under their belt.
If you come into Rogue Trader expecting Baldur's Gate 3 because they're both CRPGs, you're going to be in for a rough time.
The overall production quality of Rogue Trader is not the greatest. The characters models and animations are okay but a little dated. The cutscenes are often laughable and desynchronized. Whenever I see an NPC get shot by a lasgun in a custcene and then react to the shot 4 seconds later I feel a little embarrassed.
Where a game like Baldur's Gate 3 has detailed character animation and the entire game is voice, Rogue Trader has.... text. And a fucking lot of it.

I HOPE YOU LIKE READING!

Rogue Trader might as well be a visual novel, half the time. There is soooo much text and reading and long conversations. Almost everything that happens in that game is told via text, not shown. Again, when you take into account how small a studio is and how grand and ambitious of a game Rogue Trader is, it makes sense but it does make for a bit of tedious experience.
Maybe I'm an idiot for complaining about "too much reading" when I'm playing a CRPG but I digress.

Unfortunately, however, this problem seeps into other areas of the game. I want to talk about the character building and by extension, some problems with the UI.
You accrue levels fairly quickly in Rogue Trader. I think in my 80-ish hour playthrough I finished close to level 50. Each level you to pick different bonuses depending on your class (Archtype) and/or Origin. Most classes follow the same order (A new ability at X level, a trait at Y level, etc) but not always. So far, this is cool and all. HOWEVER, there are a few issues.
1. the difficulty curve kind of evaporated in a neutron star after Act 2 so the first 2 acts feel like they require some pretty precise builds.
2. Whenever you gain a trait in Rogue Trader, you get to pick one from a loooooonggg list of like, 50 traits. This list also changes based on your Archtype. Each trait often has a fat load of text complete with equations and conditions. In concept this is fine but in practice this is Hell. Trying to read through 90+ different traits to try and the best one and make a choice for 6 different characters in your party is maddening. I love a complex game that gives you freedom of choices on how you want to build your character but this ain't it. By the end of the game, you can pretty much pick that's good, anyways so this is only an issue at the start of the game where the difficulty is the highest.
3. Respeccing your characters (eventually) costs a valuable currency (at least in the early game) that can practically brick your run if you respec your entire party in Act 2. My first save I totally gave up because I was straight up Not Having A Good Time and thought it would be more fun to simply min-max from the start of the game, instead.

So now I'm going to rant about my experience with Rogue Trader or at least, the first 2 acts. I think acts 3-5 were pretty good and at the very least, I didn't struggle with any of the issues from Act's 1 or 2.

Alright, so Act 1. The tutorial: Pretty hard to fuck up and it's straight forward. However, once you get out of the tutorial, you are presented with an illusion of choice. You have 3 main places you can visit: Rykad Minoris, a Prison and Eurac V.
If you thought you should go to the prison first because it was closest to your ship: wrong. You go in there, get your ass handed to you in the first fight and then leave. No big deal, at least you can leave to come back later.
If you go to Rykad Minoris first: ALSO, wrong. Not only wrong but potentially dooming.
As soon as you land on the planet you and hereby locked to that planet unless you make it the majority of the way through. You only have 4 out of 6 party members and the fights ahead are BRUTAL. It's like a 4 vs 14 where there are several dudes in the back shooting you and guys run up to you and one shot you. If you someone make it past the first 2 fights, you are at least greeted with a bad ass new party member but the pain isn't over yet.
Keep in mind that you there is no perma-death or anything but if the health of a party member drops to 0 they are inflicted with traumas that can severely reduce the stats and capabilities. These traumas are automatically healed once you return to your ship BUT you cannot go back to your ship until you get 3/4 of the way through this planet. So if you somehow squeek by these two encounters but become badly damaged, you're still not in the clear and could very potentially soft lock yourself or straight up get filtered.

Anyways, how about that last planet, Eurac V? Fortunately, (well, not for me because it was the last planet I went to) it's a cakewalk! And it's how you recruit the most broken party member in the early game.
After that, you can do Rykad Minoris and the Prison and clear act 1 with ease.

The fact that the game gives you this miserable false sense of choice is absolutely mind melting. It very nearly filtered and I'm usually fairly tolerant of dumb bullshit and banging my head against a wall.
Anyways, with Act 1 out of the way, how bad is Act 2?

Well, not quite as bad, I don't think. It is, by far, the longest act in the game but I don't think you're as likely to soft lock yourself or anything, at the very least.
The one thing that does suck at first, however is the voidship combat. It's turn based space combat. And it basically sucks and you suck until you do the correct and obtuse things to get the gear to not suck. I don't want to go into too much detail but you have to get your reputation up with a specific trader but going about this is by no means intuitive.

Alright, what else can I complain about? Oh yeah. The quest log kind of sucks, too. Instead of just clicking on a quest and it showing you in which system and planet it takes place on, you have to read or sometimes it simply won't tell you. Not to mention, it's sometimes hard to know when you're "done" with a quest or planet and the triggers for progressing a quest can be obtuse.

Alright, I've been pretty harsh on the game so let's go over a quick list of things I do like.
-The combat kinda slaps. It's a lot of fun and the weapons and effects are awesome
-The music, atmosphere and environments are pretty good. Especially the environments. There's lots of little details and NPCs that make the small areas feel busy and full of grim dark life.
-While a lot of the companions are relatively one dimensional and mostly serve as representatives of their respective factions, they're still really cool and I liked the majority of them
-I thought the main story and narrative was pretty interesting and engaging, even if longwinded at times.
-Despite my qualms with character builds, I do think the character customization is pretty cool, even if it feels like there's a lot of "objectively best" builds or weapon choices for most characters. You still get to make fun choices, I feel.
-I think the encounter variety of both combat and exploration is really well varied. A good amount of enemy diversity and a lot of unique adventures and events.

And that about does it! I didn't touch on every aspect of the game--it's more just what stood out to me.
If you're curious what my verdict is, I think it's a flawed and maybe even divisive game but it's 40k and 40k rules. That being said, there was clearly a lot of love and passion put into this game and I think my love for Warhammer and the God Emperor guided me forward to finish this awesome game.

The Emperor protects. Peace