Here is the full list of all 21 Rune Lord achievements worth 1,000 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox One.
Finish the first level
Complete 5 levels
Complete 15 levels
Complete 30 levels
Complete the game
Feed the toad with 5 spiders
Feed the toad with 72 spiders
Shuffle the runes ten times during a level
Get 236000 score in one level
Do nothing for seven seconds
Perform a combo with multiplier x5
Perform a combo with multiplier x10
Perform a combo with multiplier x15
Destroy 1000 runes
Destroy 5000 runes
Destroy 10000 runes
Destroy 20000 runes
Play the game for three hours
Purchase 7 upgrades
Purchase 15 upgrades
Purchase 30 upgrades