Achievements are handed out by the Crypt Keeper as rewards at the end of the adventure in addition to XP and treasure.
They are partially to reward key points in the Adventure, but also to make up for the fact that unlike regular D&D, with its mass of magic items, there is no mechanism for imparting bonuses and extra abilities.
Achievements can also celebrate events in the scenario as well as being tied to specific locations.
Mostly give to hit, damage, skill or saving throw bonuses, with occasional special abilities or benefits.
Minor Achievements (Level 1-4)
+1 bonus to saves/skill rolls/to-hit etc. Small very specific new abilities.
e.g.. From Blood of the Dragon.
Minor: Ape Killer, +1 to hit Giant Apes (Awarded to the Player who killed the most Battle Apes during the adventure).
Minor: Understanding of Battle Apes – can recognise the signs of Battle Apes (tracks, spore etc.) and have a rough understanding of their culture.
Minor: Serpent Knowledge – can recognise a creation of the foul serpentine art of Vivimancy. (Awarded to the players who explored the lab and/or read the Serpent Men texts)
Minor: Navigate dangerous spaces. +1 to any skill rolls or saves when moving through corridors where there is a danger of collapse.
Minor: Read Serpentine. +25% bonus to Read Language roll
Freedom of the village of Cragspire.
Major Achievements (Level 5-8)
+2 bonus to saves/skill rolls/to-hit etc New abilities with broad application.
Heroic Achievements (Level 9-15)
The stuff of legends, powers outside of the normal almost magical in nature e.g. max damage with a particular weapon, always hits with sword, always acts first in combat.
Demi God Achievements (Level 15+)
The powers of the gods, eg Immortality, Touch of Death, Create Ice Castle from Water