Here is the full list of all 20 Sir Lovelot achievements.
Revisit a level
Unearth a secret treasure
Pickup 100 coins
Defeat 100 nasties
Die 100 deaths
Find 5 diamonds
Visit Swampland
Take the plunge
Collect 50 geese
Visit Spookyland
Collect 3 lollipops
Visit Volcanoland
Collect 40 daisies
Defeat the fire spitting Dragon
Meet your one and only
A flower for a damsel
Visit Jungleland
Break something
Finish a level without dying
Take a break