This is probably better suited to the thread about “bad guys dying too easy”, but I just wanted to throw out a couple adventure design principles I enjoy using for this game, that maybe can help with challenging players for others as well. Just some thoughts/opinions, take with a grain of salt, etc.
When I am creating a Conan adventure:
-Combat is usually a distraction from the groups real goal in the scene (to get through the area, accomplish some task in the area, etc).
-The purpose of having the combat in the first place is usually not to present a risk of death but to strip resources from the PCs and/or to build the doom pile for later. Complications resulting in loss of resources (medicine, loads, etc) are common in these fights.
-Nemesis or “boss” NPCs frequently have some narrative barrier to clear before defeating them. For example, if the Nemesis is a sorcerer, the players have to find and smash their magic mirror. Until then, attacks simply pass through the sorcerer (thank you, Conan the Destroyer). Alternatively, maybe the horror from the outer dark can only be harmed by the eldritch Dagger of Such and Such, which the party has to first pry from its resting place while under massive attack during the scene.
-Add Doom for specific NPCs or scenes. Usually only the one or two climactic scenes of the adventure, but there needs to be enough Doom on the table to run those scenes.
-Try to grind down the party over the course of the adventure, and don’t worry about any one fight being too strenuous. Just keep chipping away at those resources with Complications, etc, and save Doom for those one or two really big fights. As I understand it, it should be extremely rare for the party to replenish any resources outside Carousing.
-Combat scenes are built with a baseline (maybe minion and toughened Degenerates from the trees), with Doom spends to spice it up. So in that example, there are basically an infinite number of Degenerates, or as many as the GM needs. Every round a few throw rocks and spears from the trees and a few charge with clubs as the party tries to get through the area - those that charge are quickly splattered but maybe get a hit in. Spending a few Doom brings some curious giant lizards to cause trouble, or maybe a rock slide. Similar to the scene with the Picts on the cover of Jeweled Thrones of the Earth! If there is no Doom on the table for any of that and the party does not want to spend any, then it is a relatively quick and easy obstacle and small but hopefully fun part of the adventure, maybe with the loss of a few resources or a bit or armor here and there, and on to the next scene.
-Constant mental assaults - going insane from the sight of some horror from beyond space and time is almost always the bigger risk, as opposed to getting stabbed by a bandit. Increase or decrease as-needed to keep players on their toes.
-Individual threats - each party member is under attack from foes unless they are really taking steps to stay out of the fight, or is in danger in some other way. Almost always more than one attack per round, if the group is fighting a lot of foes.
-Unless the player pulls off some clever maneuver, the difficulty on attacks is usually 3 or higher due to circumstances (uneven ground, blood-slicked weapons, lighting, obstructions - which might also be giving cover!, etc).