Heroes of Terrinoth is adventure that's both abstract and detailed.
First off, let's be clear: Heroes of Terrinoth is a reskin of FFG's Warhammer Quest Adventure Card Game. WQACG designers, Adam and Brady Sadler, simply ported their design over, such that there are very few mechanical differences between the two games; aside from a couple tweaks made in the three years since WQACG was released and a slight redirection in terms of adventure focus. You're still a party of stalwart adventurers stepping into the world to solve a problem. The main difference, of course, is that of setting. While WQACG was set in GW's venerable Old World, Heroes is set in FFG's own Terrinoth; home of Descent, Runebound, Runewars, and Battlelore, 2nd Ed.
For some, that's an instant non-starter, as Terrinoth is often simply reviled for being "generic fantasy", as opposed to the 35 years of depth and character that has been layered upon the Old World or similar IPs. While I sympathize with that perspective (I still have 8000+ points of fully-painted Skaven in my basement from my Fantasy Battles days), I don't think Heroes suffers from the change in setting in any way. Indeed, in some ways, it kind of patches a thematic flaw that some could see in WQACG. Terrinoth, being what it is, is generally unburdened by any of the trappings of setting. In WQACG, you could be prone to wonder why a Witch Hunter would ever spend time with an elf of any kind. There are no such behavioral burdens in Heroes. Also, one of the advantages of the lesser known background is that it's easier to simply plug in the variety of heroes present in games like Descent, 2nd Ed., from which the bulk of the characters in Heroes are derived, without a need to explain why they'd be associating, other than the typical (generic?) desire for glory and loot (and, yes, occasionally doing good things, too.)
One distinct advantage of being able to draw from FFG's game world is that there are many more characters in Heroes than there were in the prior game, each with a subtle skill or ability that makes playing Syndrael the warrior different from playing One Fist the warrior. To the Sadlers' credit, they still managed to retain the essence of those characters' inherent abilities from their origin game, such as Astarra's ability to move the party forward (via gates in Descent; via Exploration successes in Heroes.) Given the dozens of characters present in the other Terrinoth games, it's a firmly paved avenue for expansion, as well. Like the original game, each character type is differentiated by the variations in their respective action cards. A Scout exploring can be much more advantageous than a Mage doing so, while the latter attacking is often better than doing so with a Healer. Also, the advantage of the diversity in the character pool is that the designers were also able to draw on the class system present in Descent to give upgrade cards more of a thematic lean than in the Warhammer game. Now, instead of just being better at attacking as a Warrior when receiving an upgrade, you can decide whether you're going to do so as a more durable Knight or as a more bloodthirsty Berzerker.
However, a counterpoint to that diversity in character and style is that the game is still very mechanically driven and the differences between the actions of two different characters aren't overwhelming. Much of the gameplay is based on calculation of how different die rolls are going to benefit the players or not. That's understandable in a stripped down approach that's attempting to be an adventure game played solely with cards and a few dice. But it does occasionally drain the game of the drama and excitement that is the hallmark of dungeon crawls and other games like Runebound. Still, RPGers and fantasy gamers from time out of mind have known the tension of having to make a key roll at a given moment and Heroes certainly does not lack for that. Gameplay is still quite engaging, keeping the players focused with basically no down time as the horde of creatures grows in front of you. Knowing how to work together is essential in the more difficult scenarios, which means that every player's turn will have an impact on everyone else.
An unusual departure from the typical design is that Heroes also does not have loot. You won't be finding any magic swords or staves to help you on your way because there aren't any. All of the magic items that can be discovered are single use that typically help with die rolls or do minor amounts of damage to the enemies. On the one hand, that's disappointing because one of the hallmarks of this style of game in any format is the discovery of cool weapons or amulets that let you do cool things. On the other hand, it also removes the game from what I've usually labeled "The Descent problem", which is a situation where a player discovers that epic weapon that then lays waste to all opponents and turns the game into either a rout or a situation where the GM/AI has to introduce monsters of such power that player and game end up exchanging one-shot kills with each other for an hour. As the increase in player power in Heroes is much more subtle and gradual, it does tend to be more defined by skillful play and proper teamwork, rather than finding the Destroyer of Worlds broadsword.
Also, the way that similar games and, indeed, WQACG controlled the release of these legendary weapons was by introducing them in a campaign. One either started at the beginning of the campaign and played through it or figured out how to jerry rig the gear so that characters would be powerful enough to jump into a scenario in the middle of the quest chain. Heroes removes that problem entirely, in that there is no campaign. All eight quests are fully self-contained and simply labeled with a difficulty level so that players know what kind of challenge they're getting into. For a game with so many abstract elements, it's quite refreshing to simply decide that you're going to dive into the difficult Siege of Asthill one night, rather than having to start with The Goblin Problem and work your way up over a number of sessions. The diversity in quest beginnings and goals is also very welcome; while A Foul Ritual has you wandering into the town of Haverford like typical adventurers, Battle in the Mistlands has you leading an army to the border and The Cursed Codex has you waking up in a cell. So, even considering the more mechanical aspects of the game, there is plenty of story to support it.
And that's the final interesting contrast of this game: Despite there being more quests, more characters, more monsters, and generally more of everything than WQACG, it's very clear that this is a base set. There are many, many additions that could be made to this game for relatively little cost to the buyer and especially considering the dense web of lore and character that has been developed over the past dozen years for Terrinoth. Heroes already uses two of the more notable boss monsters from Descent 2nd Ed. in Splig and Valyndra, but introduces six new ones that may get ported over to that game. If you're eager to play a hero like Steelhorns from Runebound or square off against a boss like Bol'Goreth from Descent, the possibility is high that they'll make an appearance somewhere down the road. And maybe they'll even figure out a good way to introduce some loot...