Good Ending - 

Obtain a sacred coin one of the various Mega Boss enemies that can be found within the 4 main dungeons by way of killing 10+ visible enemies within the dungeon and then giving said coin to the old crone within the sacred temple for a red feather.

Bad Ending - 

End the game without doing the above.

Worst Ending - 

Do several night sweeps throughout the city by resting in bed until you are captured three times by an unknown enemy group.

Alternate endings -

Do the above, but donate several hundred coins to the beast god's donation box, until he bequeaths you with a special elixir. Drink it A.S.A.P. 

Will also allow for certain intimate scenes and additional dialogue throughout the story.