Music Tracks
     Music  unlocks in conjunction with your save file for MGS4. So if
you have a save at the end of the game, you will have all Music Tracks
unlocked  for  MGO,  if  you have a save after you have beaten a boss,
their track will be unlocked.

     However  if you continue a completed save file, you will lose all
tracks in MGO until you unlock them again.

Ranks
     Online ranks that show next to your name:

Bear             Have a large amount of CQC attacks given

Bee              Uses lots of scans

Crocodile        Very good kill death ratio

Eagle            Large percents of headshots

Flying Squirrel  Have a high percentage of rolling

Jaws             Large Amount of Knife Kills

Kerotan          Prefers Capture rules

Night Owl        Use the ENVG a lot

Pigeon           Perfers non lethal attacks

Rat              Falls for a lot of traps

Sloth            Gets shot in the head a lot

Snake            Perfers sneaking missions

Turtle           Use the Cardboard box a lot


Secret: Singing
     During  gameplay,  in  the text menu (on either all or team) type
for  your  character  to hum/whitsle/sing a part the Metal Gear Online
melody.