Here is the full list of all 17 Sigi - there are A Fart for Melusina achievements worth 1,000 gamerscore.
Collect all SIGI's.
Clear all caves.
There she goes again.
Defeat Ivan Stinkup.
Hard to find and almost out of reach.
Find the long lost golden crown.
Find the long lost golden talisman.
An apple a day...
Defeat Kolles Terrol.
Kill 100 Zombies.
Defeat the Steel Horse.
Collect 1000 coins.
Find the long lost golden grail.
Defeat Blind John
Fart at Melusina.
In under 30 minutes?
Pocket 2500 coins.