Here is the full list of all 26 Delver achievements.
Max out on backpack slots.
Max out on belt slots.
Buy a magical elixer from Joff.
Listened to the wise.
Take 400 damage in one run.
Escaped with the Orb.
Chow down on 40 things in one run.
Grab the orb.
Zap wands 300 times in one run.
Find 5 secret areas in one run.
Use 10 scrolls in one run.
Identify 5 items in a run.
Use 15 potions in one run.
Find 300 gold in one run.
Trip 10 traps in one run.
Become poisoned 10 times in a run.
Kill 150 monsters in one run.
Make it through the Ruins
Make it through the Sewers
Make it through the Caves
Buy a belt slot.
Buy a backpack slot.
Make it through the Dungeons
Bought something from the wizard.
Bought something from Joff.
Died, for the first time.