all good answers 
Difference between the two:
Portable - Must be run from the directory it is saved in
Install - No registry keys, just a txt file in %appdata% with the install location, so dolphin can be run from any directory (file association anyone
)

Difference between the two:
Portable - Must be run from the directory it is saved in
Install - No registry keys, just a txt file in %appdata% with the install location, so dolphin can be run from any directory (file association anyone
)
