This is a personal, largely spoiler free (or spoiler-vague) review of The Matter of Britain custom campaign by Frying Tonight for Arkham Horror the Card Game.
Compared to official Arkham Horror campaigns, the Matter of Britain is light on the horror elements - it's all about the pulpy action, fighting knights and dodging cops across Britain. The major horror element present is the Black Knight - an immortal, mysterious enemy that constantly pursues you through the adventure and who you often can't do anything to stop. He always feels more like an obstacle than a threat, but the ways in which encounter cards can suddenly have him corner you are always a little nerve wracking. Still, that pulpy action is great - fighting cultists for artifacts, dodging cops, and brawling in the streets all end up very exciting.
Matter of Britain's story is a little loosely put together, but yet comes out especially strong - it focuses far more on hitting major beats than large blocks of text. After the initiating events, the story has your investigators going to important places in the King Arthur myth half the time, reliving or trying to twist events. The other half, you're brawling with cultists and cops on city streets. Sure, it's a little "And now let's go here to see what happens" - but it's quite fun, and you do want to see what will happen. There's never any question of what a scenario is about, and it's always a pleasant surprise how something will be represented. All the elements you'd want from a campaign - Excalibur, Merlin, The Lady of the Lake - are all here, and there's a lot of different ways they get incorporated based on the choices you make. The campaign also makes great use of multiple recurring villains - it introduces the actors on its stage early on, and finds new ways to use and combine them in each successive scenario. By the end, I was even rooting for the inspector who kept showing up to arrest the investigators only to get the crap beat out of him.
All these story elements are the strongest part of the campaign. There's not an overabundance of text, and the scenarios give multiple paths between them. Starting at scenario 2, most scenarios have two different paths to unlock, which cascade through the campaign in sometimes major, sometimes subtle ways. Your choice in one scenario might give you a cute bit of text in a later one - or it might give you a completely different final act for the one after. It's good stuff. This is easily a campaign I can see replaying - and want to replay already to see the other paths. Scenario 4 even gives you two choices of scenarios, with the other then used for scenario 6, with totally different climaxes depending on the order you do them. It's worth noting this campaign has a lot of fail forward, too - not only do you get to keep moving along, there's tons of special story beats and side paths you can only get for failing, or at least setting up special events that might look like a fail - while some of these are pretty well hidden, there are clues, and being familiar with the Arthurian myths can help here.
The mechanics of the campaign start fairly simply - the first scenario actually has a bunch of mechanics you don't see later, but shouldn't be anything too weird for anyone who's played through The Forgotten Age. Otherwise, the campaign tries to slowly ramp up its complexity - often doing a good job of introducing new mechanics on a scenario-by-scenario or an act-by-act basis. There's a few sticking points, however - scenario 5 ended up being one of my favorite scenarios, but its mechanics took me a few times to reread and get at first, and if you do well, it can throw a LOT of options at you in the end. Scenario 8 likewise throws a lot at you all at once - you can easily expect a dozen cards that might have weird triggers out all at once. It's doing something unique with its mechanics, but it's hard to feel like it's worth it.
The scenarios do come out strong overall, however - scenarios 3, 5, and 6 are some of my favorites (with 2, 5, and 6 acting as an excellent escalation on the whole thing). Scenario 5 manages to do a great job of having a lot of different elements in play at once, but separating them out in such a way that it doesn't feel overwhelming. The campaign also does a great job at mixing things up - it rotates between its threats well, so no two scenarios back to back ever feel too similar. It's always exciting when you return to something, instead of feeling samey.
Unfortunately, not all the scenarios are great. Scenario 4-A is an extreme one, and while I enjoyed it, I had a group very well suited to it - the wrong party might find it extremely frustrating, and there's two versions of it that require very different things. Scenario 4-B meanwhile just ends up a bit short and dull, with an objective that feels either too easy or too impossible to achieve at some player counts, depending on which version you do first. The finale, likewise, was a let down - it hinges on a complicated mechanic with a lot to track, which doesn't have a ton of payoff - and just blitzing through the scenario might be the best path, especially given how easy the actual threats, including the final villain are.
Rules wise, the scenarios are usually well put together. There's not much in the way of new, bespoke mechanics - the campaign gets by with story cards and rules you've seen before, using them well. While the first scenario introduces a lot of new mechanics you won't use later, it doesn't introduce enough to feel overwhelming - just enough to have its own flavor, which is fitting into how it's story acts as a gateway to the wider campaign. Scenario 4-B does have a bit of an unclear rules hitch, with a massive enemy with "prey only" against an asset card - but I recommend having it so that character does exhaust to attack investigators at its location. Scenario 8 introduces the campaign's only real complicated mechanic, and unfortunately, while it's a neat idea, it feels like a dud - taking too much calculation and effort to interact with. One last thing is many scenarios have a "memory flag" that can turn on and off for each investigator individually - it might be useful to have some sort of token you can use for that, but that should be easy enough.
Still, those quibbles don't take away from the campaign as a whole - The Matter of Britain is worth diving into, especially if you want a campaign that focuses more on pulp adventure, and has some wild story paths.
More on Matter of Britain:
The Matter of Britain: Spoiler-Light Review