- Draw the outline (Free Select Tool with antialisaing and Feather edges radius to 20) and save it as path
- Select > Border > 4px (Border style Hard)
- Select > Feather > 5px
- Fill with outline color
- Select from previous path
- Select > Shrink > 2px
- Fill with background color
Filters > Blur > Median Blur > Radius: 6
- "Water Swirl" by InspectorJ of Freesound.org
- "Underwater ambience" by akemov of Freesound.org
- "Perspectives" by Kevin MacLeod of incompetech.com
- Main theme and all sounds FX were kindly made by Nullrate