For context, I write this review after achieving 100% of achievements on Steam (meaning completing much of the main campaign, pretty much all of the Jaws of the Lion expansion other than mutually exclusive missions, and all of the Guildmaster mode's non-repeating missions) which took me 380 hours, including significant time playing in campaigns with friends. Additionally, I own Gloomhaven and Jaws of the Lion in physical board game format. I never finished JotL in physical, but I've pretty much played the base game to 100%, completing every personal quest and every single scenario that wasn't locked out by campaign choices, maxing every class to 9, and even exhausting all of the city and road events until there were just repeats left. I certainly didn't time all that but given the game takes a considerable amount of time to set up, I doubt it was less than 200-300 hours, all told, if not 400-500. Thankfully, this review only took half that long to write!
And yet, while unsurprisingly I on balance really like the game, I do have my qualms with it. As the above indicates, one thing I can certainly say about Gloomhaven in its favor is that there is no shortage of content. Even with all of the above, the digital version has solo missions that I didn't even bother with and within the last year, the physical version of the sequel, Frosthaven, released, which as I understand it is like 1.5X as big of a game (though I honestly haven't looked into it much). If you're the type who has no interest in a game that's going to give you less than 100 hours of playtime, have no fear, there's plenty.
However, while the game is able to boast impressive stats regarding its content, there is a point where the aim for quantity overtook quality. In the base game especially, the missions can get extremely repetitive in format. Just about every map has some quirk either in layout or enemy grouping or with a special scenario effect, but of the 95 scenarios in the base game, without doing any actual research, I'd guess at the very least, 75% of those the win condition is "Kill all enemies in all rooms." And it's honestly probably closer to 85-90%. To be fair, some of the worst balanced scenarios are when the game deviates from this formula, but it is still a little frustrating for a game that has so much creativity to feel like a hefty chunk of its scenario pool is a bit lazily designed at times. This may also be lightened by the fact that most people don't really need to play near every map, many of them are branching paths on the main quest, others are entirely side content, and a good number are specific to certain personal quests. So you could certainly play the entire campaign while only doing maybe half of the scenarios. I also think Jaws of the Lion, while a significantly shorter campaign, does a much better job of this with a variety of mission parameters and only one of them is clearly improperly balanced that I noticed.
One of the main things Gloomhaven is known for other than its massive library of content is that it is punishingly difficult. There is definitely RNG involved, but it is a heavily strategic game that requires learning the ins and outs of your classes as well as the enemy types and their various capabilities. While I find the difficulty is generally at a really good place of very challenging, but fair and doable, there are certainly some scenarios that feel heavily imbalanced. This is especially so in Guildmaster mode which was clearly a very thrown together game mode utilizing the base game's random scenario generator. One mission would be a breeze and the next would require you to exploit the most overpowered abilities at your disposal just to skirt by with significant luck. This is only somewhat forgivable to me due to the fact Guildmaster is clearly a mode put together to troubleshoot and develop the digital version, rather than as a replacement for the main game. Further, there are several difficulty settings, including a casual mode that makes most any scenario a walk in the park. A few enemy types also seem clearly broken for how they're employed and I was disappointed to see the recent second edition errata didn't fix basically any of it. Still, the bulk of the game is very fun with its challenge and victory feels well-earned and rewarding. I will also note that the title of this review is a reference to the catch phrase my friends and I would use every time something really bullshit happened in a session.
I will also caveat that the game definitely gets significantly easier as you go. I don't want to get into the details too much, but your d20-like RNG to determine how well you hit is based on a deck of attack modifiers and at the start it's pretty balanced with good and bad modifiers, weighted to a neutral +0 average. But when you level or get perk points, you get perks individualized to your class that remove/replace bad modifiers and give you good modifiers, so by level 4 or 5, you can have a much more dependable RNG and once you raise your prosperity level by completing quests, your characters will start at higher levels and with additional perks so even new characters don't have the struggle of such a crappy mod deck, which makes a huge difference in consistency and strategy when your big attacks are unlikely to totally whiff when you really need them.
While I could rant all day about the various mechanics, one of the last main things I'd like to note is that the base game features 17 classes, 6 of which you start with, and the rest unlockable through completing your character's personal quests that are relevant to the unlocked class. The community is extremely strict about spoilers, so I'll be vague about the unlockables but I find the classes in Gloomhaven are very fun and varied, each capable of 2 or 3 different play styles that each feel unique and, for the most part, viable. There are certainly classes I think are significantly weaker or significantly stronger (of the initial 6, tinkerer may be the weakest class in the game whereas Cragheart and Mindthief may make top 5 or so strongest of the entire pool), none of them feel useless and I thoroughly enjoyed playing with each of them. Jaws of the Lion also adds 4 new classes and while comparing their strengths when I played them on very different scenarios for that campaign is difficult, I think design-wise, they were even a step above the classes in the base game when it comes to just being fun and unique. A huge pull of Gloomhaven is unlocking and exploring new classes and this is one reason the community is so adamant about spoiler tags, because it's widely accepted that some of the initial excitement is when you unlock a new bad ass class and get to explore everything it can do.
Most of the above could be said about the physical or digital versions of the game and that's because in a lot of ways, this digital version is a pretty faithful recreation of the same experience so commenting on the board game is sufficient. However, I will note a few things about this adaptation. For one, the Guildmaster mode is a pretty big variation on the game with tons of new content not in the board game. Personally, I felt this was the weakest content and again, I think it was mostly thrown together to playtest the digital version, but it does have some features that I like more than the base game. Aside from extra content, the digital version is mostly very faithful and a good adaptation of the rules, which is significant for a game that has so much variation and some pretty complicated rule sets. I have noticed a few things that I think are glitches because they don't align with any reading of the rules I can make, at present the biggest one being that in the current build, a monster that has an ability that taps an element is allowing all monsters of that type to tap that element when it should just be the first one who uses it up. This isn't always that bad but with a certain enemy type can mean your entire party loses their turn due to a glitch, which is awful, though most of the game works well.
The presentation of the game is okay. For a game made in the last few years, the graphics are on the low side and can be a bit visually glitchy at times, but I found them functional for portraying the board game setup while still managing to add some colorful scenery the tiles of the physical game lack by practical necessity. Another massive advantage is that each scenario of the board game, even if you leave out your character mats on the table, can take a good 30 mins to an hour to set up, even if you're quite practiced at it. It's a fun game but that got extremely exhausting and it's so nice having the digital just do all that with a quick loading screen. There's also the benefit that the game does interpret the rules for you so you don't have to look up much. I even learned a few minor rules I was doing wrong from playing it. As a last significant plus, the digital version is tremendously cheaper than buying the board game. At present, the main game is $35 (all prices here are in US$) which may seem a little steep for a game that's admittedly not all that impressive graphically. However the physical version of the base game is going to run you closer to $110, maybe $80 if it's on a good sale, but you'll also likely need a box sorter (I'm NOT kidding) if you want the sorting and setup/teardown to be at all efficient and that can run anywhere from $40 for a crappy one to $80-100 for a more adequate one . The only major downside is that the tactile feel of the physical board game is admittedly very nice and despite the expense, it's a very nicely made game with minis for each class you can paint if that's your thing.
My on balance feelings toward Gloomhaven are surprisingly mixed for a game I've sunk so much time into. I think my recent experience makes me feel more like 4 stars as while I never was exactly "tired" of it, the novelty certainly wore off after so long. I wasn't forcing myself to play through the last 150 hours by any means, but it felt far more like something to just do for a bit for a break from other things rather than the excitement I got in the initial playthrough. However, for this review, I have to keep in mind that initial excitement and addiction, which was rather significant and consuming. Given that, I think I'd be lying if I gave Gloomhaven less than 5 stars. My biggest recommendation is that honestly, you really don't need to see all the content the game has to offer. It is a long haul game, but you could get plenty out of it without playing it for like 700 hours or whatever.