Here is the full list of all 24 Pixel Boy and the Ever Expanding Dungeon achievements.
Die 100 times
Try every power up in the game
Open 100 treasure chests
Pickup a total of 100 keys
Use Pixel Boys computer to check out a super awesome game.
Complete Act 4 up to the first boss
Complete all Acts
Defeat the Final Boss
Defeat all four bosses in the game.
Obtain 10,000 coins
Complete Act 3 up to the first boss
Defeat Frank Indadark
Defeat Penta Vultis
Spend over 500 coins on power ups
Use each one time use power up at least once
Open 10 treasure chests
Complete Act 2 up to the first boss
Obtain 1500 coins
Hold 15 keys at a single time.
Complete Act 1 up to the first boss
Defeat Moby Richard
Obtain 150 Coins
Enter the Dungeon and receive your Pixel Powers
Complete the Tutorial