Here is the full list of all 35 Desktop Dungeons: Rewind achievements.
Get 6 full conversions in one dungeon run
Gain a level in the middle of a fight to defeat a regular level 10 boss
Kill an enemy three levels above you
Kill an enemy one level above you (any standard dungeon)
Break completely through an enemy's physical or magical resistance
Block 1000 points of regeneration with burning or poison
In a standard dungeon, kill any enemy with the Burning effect by striking another foe
Kill an enemy five levels above you
Kill an enemy seven levels above you
Kill an enemy nine levels above you
Immediately convert ten items bought from standard dungeon shops
Petrify an enemy, then earn more than double its experience value on your next kill
Earn extra experience from five enemies in a standard dungeon run while they're slowed
Have Might, Death Protection and Stone Skin active at the same time (from glyphs or other sources)
Destroy ten walls with PISORF in one standard dungeon run
Discover all god likes and dislikes
Spend piety on two different gods in one dungeon
Spend piety on four different gods in one dungeon
Reach 200 maximum health
Reach 150 total damage
Reach 25 maximum mana
Use five different poison cure methods in a single dungeon run
Waste fewer than 50 tiles of regeneration to win a standard dungeon run
Upgrade any hero guild to level 3
Fully upgrade your Kingdom
Replace a locker item when all guild slots are full
Spend at least 300 gold on preparations for a single dungeon run
Complete all bronze challenges
Complete all silver challenges
Complete all gold challenges
Unlock the Vampire
Unlock the Gorgon
Unlock the Half-Dragon
Unlock the Goatperson
Spend 100 hours in the dungeons