Alright let me preface this, I never ever write anything close to this, and I don't really ever contribute to a game via this option since I'm not really bothered to. With that said I love the 40k universe and especially the Adeptus Mechanicus are my favorite "faction" by far, so when I heard a tech-adept would be added into Martyr I was very happy and purchased the DLC on the first day. I'm writing this because Martyr's potential is vast, and for recent 40k games that is to dang rare to pass up.
Starting out with the story, it was interesting and kept me coming back for more, which is a good thing, but it could've been done a lot better. If you wanted to focus the mechanics on Cybernetica that could've easily been done by just having the adept be a fully ordained priest. Anyone with an inquisitorial rosette is an inquisitor no matter their cult beliefs or their other sworn allegiances. All it takes is three inquisitors or one lord. Not only would this allow more interesting interactions with him and the tech-priests on-board, but he could have very interesting interactions with the local conclaves. This could've also allowed you to play around with his model a bit more, since it is a bit lackluster in my opinion; he looks mostly human, and even an unordained adept would know full well that technical implants, especially in his line of work, would be of greater value than fleshy bits. I'll uhh... digress from this point. Again props on the story.
The psiloi(s?), why are they even relatively a thing? I truly don't understand why they exist when you could've just added in the scyllax guardians that you could make as powerful, but they would be backed in lore and be a little bit more advantageous when used by a tech-adept who is constantly destroying the worst of the Imperium's enemies. When looking at the scyllax vs the psiloi you can easily see the similarities. For example, the scyllax have a claw variant that shreds people to death, and they also have a bolter version of the scyllax that would just function as the combustor psiloi, but actually pack a good punch, since they have bolter might. From a lore perspective and mechanics standpoint, I just view them as working a lot better. Not to mention scyllax look WAY cooler, no offense.
The Adepts arsenal makes me want to literally cry. A glance at the armory available to an Inquisitor, especially one trusted (relatively) by the Adeptus Mechanicus would be a lot more than 4ish(8ish Alpha/Beta) weapons. I like the ideals behind the weapons as they do get the job down for the first twentyish levels, but beyond that, it taxed my mind as to why the Melta Gun isn't available to you, or the plasma pistol, or how about any of the amazing weapons that could be wielded by an Adept. You could also have made a really cool variation of the bolter where it works out of a mechadendrite, but that is some wishful thinking (not knocking the devs I just love the power behind mechadendrites.) An Irrad Cleanser and rad grenades would be an amazing addition to the game, you could push the fold of the Tech-adept becoming a minion and DoT damage class, since currently when I shoot an enemy they laugh in my face. Phosphex grenades could be his heat damage DoTs aswell. With his current war-gear he doesn't could a candlestick to let's say: a Psyker, a plasma cannon wielding Crusader, and an exitus toting Death Machine, he should have volkite at his disposal. I know in lore it is rare, but he is an Inquisitor, who already has Kastelans (The Legio Cybneticas' most prized positions, they also clearly have doctrina-wafers which is literal gold... I digress). My main point behind the Adept being able to stand up for himself is the fact that the current A.I are a bit messy when pathfinding and his own DPS is abysmal, and that would be ok if the constructs could hold their own.
The constructs (minus psiloi(s?)) are pretty well done, like most of this DLC, but some points need to be expressed. All of them are ok and cool, except for the turrets. That is a personal opinion as I'm sure they can be built into a build revolving on cooldown reduction and using the passives in the game to buff their damage, but it is in ARPG, so semi-fast paced should be expected. For the above mentioned Irrad Cleanser, it could be a tarantula turret module, not lore accurate, but it would be pretty cool. The Kastelans need a hp and damage buff, flat out. In higher levels, they just aren't scaling well. Mostly everything else about them is pretty cool not gonna lie it is one of the best parts of this DLC and props where it is due.
Thanks for reading, and I guess I'm sorry about no TL;DR, but it would just ruin the whole point of this rather short essay. Feedback would be liked, and if my brain is going too far lemme know it tends to happen.