Here is the full list of all 63 Pixel Dungeon achievements.
All scrolls identified
10 games played
Death from falling down
All potions identified
17 points of Strength attained
20 pieces of food eaten
6 potions cooked
Level 18 reached
Item of level 9 acquired
3rd boss slain
Collected 7500 gold coins
150 enemies slain
Item of level 6 acquired
Level 12 reached
2nd boss slain
3 potions cooked
Monster killed by a Grim weapon
15 points of Strength attained
Collected 2500 gold coins
Item of level 3 acquired
10 pieces of food eaten
Level 6 reached
1st boss slain
50 enemies slain
13 points of Strength attained
Collected 500 gold coins
Collected 100 gold coins
Level completed without killing any monsters
10 enemies slain
250 enemies slain
Level 24 reached
4th boss slain
All rings identified
All wands identified
All potions, scrolls, rings & wands identified
All bags bought
Ring of Haggler obtained
Ring of Thorns obtained
Amulet of Yendor obtained
Amulet of Yendor obtained by Warrior, Mage, Rogue & Huntress
Pixel Dungeon left
Challenge won
Death from fire
Death from poison
Death from toxic gas
Death from hunger
Death from an enchantment
Death from fire, poison, toxic gas & hunger
19 points of Strength attained
30 pieces of food eaten
40 pieces of food eaten
Item of level 12 acquired
9 potions cooked
12 potions cooked
100 games played
500 games played
2000 games played
1st boss slain by Warrior, Mage, Rogue & Huntress
3rd boss slain by Gladiator, Berserker, Warlock, Battlemage, Freerunner, Assassin, Sniper & Warden
All rare monsters slain
7-hit combo
6 piranhas killed
15 monsters killed at nighttime