Gloomhaven's scenario failure condition creates an important design decision: the game allows you to fail and retry rather than forcing campaign progression regardless of outcome. Failing a scenario preserves character progression and equipment. The only penalty is time and the cost of refreshed supplies.

This design choice is the correct one for campaign games targeting a broad audience. Permadeath-on-failure would create scenarios where unlucky combat rounds end campaigns prematurely. The retry mechanic allows genuinely difficult scenarios to exist without being campaign-ending.

For groups that find Gloomhaven too easy: the enhancement system allows cards to be upgraded at the cost of gold, creating a long-term power increase that changes the difficulty curve. Groups that optimize their class cards aggressively will find the game's challenge drops. Playing conservatively on enhancements extends the challenging period of the campaign.