So I've been aggressively trying to win this on my paladin to start with, as I'm most familiar with that class. But I keep consistently losing, sometimes as early as round 3. Only once did i actually get to the last boss, which promptly destroyed me. I've been using the Icy Veins paladin guide (https://www.icy-veins.com/hearthstone/paladin-dungeon-run-class-guide). My biggest issue is that most of the time the treasures available are all sub-par, and if I do get something decent, the card bundles available afterwards aren't really a match for the treasure... trying to build synergy into the deck just keeps failing due to the total RNG involved.
I do think the practice has been good and I feel like I'm learning good lessons about how to build a cohesive deck, when to hold off on playing something until the right moment, and when to just go all in. Im just a bit frustrated that i just keep failing over and over (and getting no permanent cards or gold from that play mode doesn't help me maintain my enthusiam).
the trick with dungeon run is that your deck has to be something really really unfair uhmm with Pala there are two ways to achieve this, using the "Dude" sinergy or forgetting the dude sinergy and just go for a smooth curve and a lot of value, preferably with summoning scepter but if you don't have access to it in your run then a smooth curve goes a great length to help and even then at certaitn point you want to smooth out your win conditions so that you have multiple of them, for example in Dudadin you'll want to pick a Lich king instead of mroe dude sinergy at certain point,
I'll also say that you should try other classes first even if you aren't as familiar with them, particularly Mage and Jade classes with double battlecry,
edit: also...that guide has some....questionable advise, it says taking MC is bad, but tbh taking MC with 2-3 secrets is great, it won't dilute your draws and will thin the deck which ends up being really heavy by the end, it also says Potion of vitality is bad, . when that's the whole reason you wina gainst some bosses..plus it reccomend's picking khadgar's orb when most of the paladin's spells won't see too much difference by being 1 mana lower.
Honestly I consistently get to the last boss on most classes, and then it's an RNG-fest. I think I won on paladin with the passive always stealth card and the totally broken 'evolve 7 times' card. If you can get that card, always take it. I've won so many times because of it.
I defeated DR with - Warrior (c. 15 attempts); and - Druid (2 attempts). Now, struggling with Rouge, because given cards are sh1it.
Even if it is a frustrating RNG sh1tfest and huge time sink, at the same time I'm enjoying it, because of some really fun (always different) encounters and because of huge satisfaction if you succeede to defeat those bosses and dungeons against all odds. I've learned a lot about cards and I have a chance to play with so many powerful and different cards, too.
With time you get some experience which helps make runs less painful. Some treasures and sets are better then other. You, also learn bosses - their cards, powers and behaviors.
The point is to have fun with the game. At times, DR is more fun to me then playing dull PvP games and collecting gold. So, rewards aren't neccessary if I alreday have fun.
Both runs I finished, Vitality treasure helped me the most. And big minions.
The craziest thing which happened to me was vs. a last boss during my first Druid attempt. I played that one card which fills the board with legendaries (for 10 mana). But it spawned some minion which destroyes all others if they get wounded. AI managed to wound every legendary and then destroy them with the help of the mentioned minion. Even with restored health and AI on 20hp, I never recovered. Insane how unlucky I was, and I couldn't beleive AI knew how to destroy every single legendary. Worse, I could have won, if I didn't play that card.
I beat them all with every class easily. But I've lost over 100 times with rogue. Rogue is by far the worst because it is 110% dependent on RNG bucket luck. This is one of the worst games in Hearthstone, and that's saying a lot.