Here is the full list of all 10 Into the Pit achievements.
Collect 6 Key Runes
Collect 25 Support Runes
Rescue 45 Villagers
Collect 100 or more Motes of Wealth
Enchant a Support Rune to Max Level
Complete 5 Dungeons
Complete 10 Dungeons
Complete 15 Dungeons
Collect 36 Journal pages
Cheat Death three times in a single run