This is a personal, largely spoiler free (or spoiler-vague) review of the fan-made scenario The Labours of Hypnos, part of the Mythos Deviations collection by The Beard for Arkham Horror the Card Game.
The Mythos Deviations are a collection of scenarios design to be added into the existing official campaigns. The Labours of Hypnos is designed to be played as part of the The Dream Eaters, after any of the scenarios in The Dream Eaters (with differences depending on what side you play it on!), or as a standalone scenario or side scenario as normal.
The Labours of Hypnos wants to be played on both Side A and Side B of Dream Eaters - with half of its locations and encounter cards staying the same regardless of the side, and half changing to suit what side you are. It's more use of the most iconic cards from The Dream Eaters - zoogs and hidden cards for side A, and spiders and cards that attach to locations for side B. Both sides feel good, although the cards that interact with hidden cards feel more natural than the cards that interact with cards that attach to locations - as the location attachments restrict movement, they demand to be gotten rid of immediately, while the hidden cards can be carried around. Still, side B works, even if not as well as side A. Through the scenario, you're weakening a powerful enemy that's going to try to kill a card you want to protect - with completing locations weakening this enemy. This makes for an interesting timer in theory, although it's not terribly difficult to defeat the scenario before any damage is even dealt to the target, making the whole mechanic a bit superfluous.
The big question is - is this worth playing twice? While there are changes between the two scenarios, they're not major - the locations are largely just mirrors, and the strategy, major mechanics, and climax are the same. There's some small amount of interesting connectivity between the two scenarios, which care about what order you play it in. Besides that, though, it's largely just the same scenario twice. Still, it's a good enough scenario - so if you do want to play it on both sides of the Dream Eaters campaign, it might make sense to play it on one side earlier than the other. It does feel like it integrates into the campaign well in terms of mechanics - both side still feel like Dream Eaters scenarios.
With a 19 XP party, I found The Labours of Hypnos to be of a good difficulty. Your ability to handle swarming enemies will largely determine the difficulty of it - there's no major threat in this scenario that doesn't exist elsewhere in the campaign.
The Labours of Hypnos is a fun scenario that can help pad out your Dream Eaters campaign and let you use your decks for a fifth time while still fitting the campaign mechanically - but it may not be worth playing on both sides if you crave novelty.
Rewards
Scenario Cost: 2 XP, or 1 XP as part of a The Dream Eaters campaign
Potential XP Gain: 1 (locations) +2 (The Crawling Mist and Dream of Eris, in the encounter deck on Side A or 2x Gray Weavers on Side B) +1 (Dream of Zeus) = 4 XP or 2 XP after cost, or 3 XP if part of a The Dream Eaters campaign
In addition, on scenario success one investigator may choose to add the Waters of Lethe card to their deck, and for the remainder of the campaigns, the Whispers of Hypnos encounter card only gives a -1 penalty to skills instead of a -2.
More on Mythos Deviations:
Mythos Deviations: Overall
Lines of Reality: Review and Rewards
Pictures at an Exhibition: Review and Rewards
History in the Making: Review and Rewards
Event Horizon: Review and Rewards
The Labours of Hypnos: Review and Rewards
The Wreck of the Albatross: Review and Rewards
Mythos Deviations Investigators