This is a personal, largely spoiler free (or spoiler-vague) review of the Machining a Mystery fanmade campaign by PuertoMateo for Arkham Horror the Card Game.
Machining a Mystery is a seven scenario long campaign set in a setting that's a cross between cyberpunk, steampunk, and fantasy, drawing on settings like Shadowrun for inspriation. The story of Machining a Mystery is fairly standard stuff - trying to get to the bottom of a conspiracy, the investigators have to poke around at factories, city slums, docks, and the like. Light on story, the campaign feels overly full of everything else - too many mixed and incoherent aesthetics, too many mechanics, and too much going on.
The premise of Machining a Mystery is pretty basic, with little in the way of story text - which isn't necessarily a bad thing, but does end up feeling very thin - it seems to just want to hit the major locations you'd expect, without any real coherent throughline. The premise is just too thin for what wants to be a big conspiracy. In a complaint that will be repeated, it also suffers from just having too much in a way that feels like nothing is actually happening or being done. The nonlinerity in the middle of the campaign, where three scenarios can be done in any order, doesn't help - because it means there can be no actual progression for any of them. There's also no sense of place - there's hacking, computers that appear powered by steam tubes, robots, cybernetics, and just a giant mix of everything with no real focus, no sense of place or design. This is further hurt by the art. A terrible, blurring filter is put on all of the card art, making it hard to tell what is being looked at, and makes everything look bad. Much of the art is also unaccredited cosplay photos - and while fanmade campaigns often use other people's art, using real pictures of people without any acknowledgement leaves a bad taste in my mouth.
Even if the sense of "everything is here" could be ignored in the setting and story, it can't be ignored in the mechanics. Every scenario is throwing out some new mechanic that's only used once, and is often far more complex than it needs to be. There's special hacking rules (used once), fire spreading rules (used once), shipping container crane manipulation and searching rules (used once), and so on. Each ends up being more complicated than they need to be for little effort - the hacking rules, for instance, have you spend clues to get a chance at success, but you can just spend clues to make that chance gaurenteed - and there's no real reason not to, so it just ends up wasted text. The campaign also introduces a ton of new player cards from the first scenario, many of which give minor benefits but still ask to be tracked. This is all topped off by the tablet chaos tokens giving a penalty or bonus based on how your investigator traits match the location's trait - which can also be influenced by other new cards you have in play - causing you to check multiple different cards just to figure out what a token's modifier is.
All of this leads to a feeling of being bogged down, and the scenario design tops that off. The scenarios as a rule tend to have too many locations, often requiring additional set-up mid play. Needing so much time to get around is made worse by encounter cards that just add to it - like aloof enemies that make entering any location they're in or adjacent require two actions, cards that punish you for moving multiple times, and more. Information on how things work are often seperated across multiple cards and in the campaign guide, requiring constant cross-referencing. And worse, none of this feels particularly worth it - it all comes across as busywork for scenarios that don't bring anything new or exciting to the table, and are just trying to hide basic gameplay, drowning it in mud instead.
Overall, Machining a Mystery is a too-ambitious attempt at a campaign that ends up including everything but fun.