This is a personal, largely spoiler free (or spoiler-vague) review of the Jumanji fan-made campaign by The Beard for Arkham Horror the Card Game.
Based on the 1995 film, Jumanji is a short, 4-scenario campaign in which the investigators are called to investigate the Jumanji board game a friend of theirs found - only to discover the game already in progress, and the magical jungle quickly overtaking Arkham. With just four scenarios, the campaign pulls off a great feeling of escalation - widening the scope each time, and focusing further on an initially established mechanical core. The highlight of the campaign is how it models the constant threats emerging from the game, playing with the encounter deck in unique ways to do so.
Mostly following the plot of the film, there's nothing in the way of story twists here - but there doesn't need to be. It's a simple, straightforward retelling adapted to Arkham Horror, and doesn't take long with textual set-up before just diving right into the scenarios. What it does do is have the mechanics fit well to the story it wants to tell, well representing the chaos that emerges in fiction every time a new turn is taken in Jumanji. While some familiarity with the film is certainly helpful, it shouldn't feel needed to enjoy the campaign.
Where Jumanji excels is in the constant presentation of choice, and throwing unique threats at you that force you to adaptation and improvisation, reprsenting its core conceit well of the jungle being something that has to be played around rather than just fought. The biggest threats are always player initiated, be they moving the acts forward to bring on new threats, or dealing with encounter cards that force unpleasant choices. Even the softest encounter cards often force changes of plans by altering the cost of various important actions or putting caveats on things players want to do. With four scenarios to work with, the campaign makes use of its limited space well - there's a natural escalation, which each scenario building on the last mechanically, serving as a perfect "And now, this happens...".
While Jumanji has plenty of unique mechanics, most are tied to only a single scenario - exploring the possibility of them and then moving on. It's the usual twist on "typical arkham" that can be expected, with none of them being too complicated or too far from the usual play experience to be a problem, and all of them suiting their scenario well. The one that does make a repeat showing is the encounter deck growing - to represent Jumanji manifesting new threats, when the the game is moved forward, new encounter cards are shuffled into the encounter deck, with which sets being used random each time. This is the campaign's big trick, and it's an exciting one, also introducing replayability to the second half of the campaign.
With only four scenarios, each of them has to be a standout to really sell the campaign - and luckily, they do! Scenario 3 is the biggest standout, making the best use of the variable encounter deck, and the finale following it up well. If there's a downside in the campaign, it's that the first two scenarios lack much in the way of replayability - although the second scenario has a unique enough twist and its main mechanic can develop in enough different ways that it likely won't feel too repetetive.
Jumanji doesn't have a lot going on in terms of rules complexity, although it does make you stop and analyze your situation in the later half, as there are a lot of unique enemies - and the encounter cards are pulling from a large, randomized set. There are no real catches or complex mechanics going on, and things flow smoothly. The only potential issue is dealing with the "Turns Taken" mechanic - during certain scenarios, you mark down you've taken a turn of Jumanji in the campaign guide, and a lot happens at once. Story cards, encounter cards, deck shuffling, act flipping, and finding set aside cards can all happen at once - and it's easy to miss a step, and lose where you were as a result.
Jumanji is a solid, exciting campaign with no cruft. If you're looking for a shorter campaign to play that leverages Arkham mechanics instead of inventing totally new ones, it's a strong recommendation.