Epochs unlock through two methods. First, normal play progression — completing runs (win or lose) accumulates Epoch progress automatically. Second, character-specific milestones — clearing specific acts, defeating a set number of bosses, and reaching higher Ascension levels.
Co-op runs count toward Epoch progression. You do not need to grind solo to unlock content.
Each Epoch unlocks a mix of content: new cards added to the card pool, new relics that appear in chests and shops, new potions, playable characters (some characters are locked behind Epoch progress), and Ancients — the NPCs that replaced Boss Relics with act-start blessings.
This is the biggest difference from STS1. In the original game, beating a run or reaching a milestone instantly added new cards and relics to your pool. In STS2, you must go to the Timeline screen from the main menu, check for newly unlocked Epochs, and manually activate each reward.
If you have been running games without checking the Timeline, you have likely missed significant unlocks. Check it after every few runs.
Before v0.98.2, a bug could freeze the Timeline screen, preventing players from unlocking or claiming Epochs. This was fixed in the v0.98.2 hotfix on March 6, 2026. If you still experience Timeline freezing after updating, the Steam community discussions have workarounds.
