Here is the full list of all 21 NeverEnd achievements.
Beat the game
Kill the final Boss
Kill every mini boss in one run
Get 20c in one run without the Rod
Walk through 100 rooms in one run
Finish the second quest
Kill your first mini boss
Buy a Bow and a Rod in one run
Finish the first quest
Kill the dummy
Find one elemental sword
Walk into a room with 6 Zomborgs
Die in the first 10 seconds
Buy your first item
Kill your first enemy
First death
Buy all items
Collect all hats
Konami code
Complete the game with the stick
Kill 50 enemies with the bow