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