desktop + startmenu icon will be changed:
open installscript.iss
Code:
;#define CustomBinaryIcon "SonicGenerations.ico"
delete the underlined sign so it looks like this:
Code:
#define CustomBinaryIcon "SonicGenerations.ico"
change the icon file to your one (example: SonicGenerations.ico => Game.ico) and put it next to the installscript.iss and compile