Survive 40 days

Hitting day 40 in 99 Nights in the Forest marks the transition into the mid-game, and although the badge is still rated 2 difficulty stars, the requirement to "reach the 40 day mark for the first time" is noticeably harder to sustain than the earlier survival tiers. Resource demand scales with the days you have already lived, so the colony you built around day 30 must now be actively expanding, not just holding.

By this point you should be running a self-sufficient base: a steady cooked-food rotation, multiple heat sources, and at least one player or NPC permanently assigned to tend the fire while others gather. The forest also gets meaner here, with stronger night encounters and larger wolf packs, so investing in upgraded weapons and armor before day 35 is what keeps a single ambush from collapsing the run.

The reward is 4 diamonds, the same flat payout as the lower tiers, which makes day 40 more of a personal progression marker than a diamond grind. Stockpile aggressively during daylight, never let the central fire die, and keep your weakest survivors close to camp so a cold night or a sudden attack doesn't undo nearly six weeks of careful play.