Ecco The Dolphin Wiki
      Reunite the brothers, Learn The Turtle Song, Shark Song & Fish Song.
                       Defeat the Great White Shark (GWS).
For the DREAMCAST version you will start in the alcove with the 'Racing
Dolphins'.  You need to go out of the alcove and turn left to find the 'Shark
Fighting Dolphin' that is the start position of the PS2 version.***

From your start position go to your left and follow the corridor.  When you see
a gap in the wall on your right, go through it and talk to the two Racing
Dolphins.  They will inform you of how to join them in a race.  After winning
the race, go back to where you started and you have to jump over the lowest part
of the wall to enter the second section of this level.  If you haven't noticed
already, you now have your first enemies in the form of regular sharks.  They
require three hits to kill them (a 'hit' is when you charge them and they flash
red and 'moan').  After jumping over the wall and swimming past the group of
sharks, the game will take control of Ecco as a small dolphin swims up and asks
you to help save his turtle friend from the sharks behind you.

After you have killed them (three in total), the game will take control again as
the small dolphin swims up and bestows the Turtle Song on you, as well as
mentioning about his brother being a better fighter then you.  Go back to the
dolphin that spoke to you at the start and talk to him again.  He will tell you
to lead him to his brother and he will teach you a song.  Jump back over the
wall to the small dolphin and you will enter another section of loss of control
as the young dolphins brother gives you the Shark Song.  This will stun and
confuse a shark for a few seconds so you can hit them head on with no damage.
After this carry on into the rest of the level and follow the wall on the right.
This will lead you into a section with a dolphin chasing a LARGE fish.

If you catch this fish, the Dolphin chasing it will teach you the Fish Song,
which allows you to lead a school of fish.  After this, go out into the next
main chamber of the level by going through the gap in the wall and follow the
wall on the left until you come to a tunnel entrance with jellyfish at the start
of it.  Nearby on the floor is a school of yellow fish.  Guess what! The tunnel
has no lights and the fish glow in the dark (coincidence!).  Make sure you
recharge your air meter (you'll need it) and then sing to this school of yellow
fish to make them follow you.  Once you are in the tunnel, take your time.  Your
air will last longer then you think, and if you go too fast you will lose the
fish, as they can't travel very fast.  This tunnel will lead you to the GWS

Once in the pool, you need to attract the attention of the GWS, so do your best
to tick him off in any fashion possible.  To kill him you have to FIRST get him
stuck in the LOWER of the two holes in the central column of rock in the pool.
Once stuck you can collect the Vigour Star Glyph from his mouth. This will give
you the ability to use the Power of Vigour that is stored in the higher of the
two holes.

***There is another tunnel that leads you to the GWS pool, which has red fish
near it.  If you sing to these red fish (don't eat them, they are bad for you),
they will protect you from the piranha fish that are in this LIT and SHORTER

There are various methods for killing the GWS, but make sure that you have
collected the Vigour Glyph before you try to attack him.  You can get him stuck
in the hole, or swim behind him and hit him.  Whatever works for you!  After
killing the GWS, exit the area by going through the tunnel that is NEXT to the
dark tunnel.  This will bring you out ALMOST back at your original start point.
Just follow the corridor to the other end and you will remember where you are.

After re-tracing your steps back to the Fish Song Dolphin, go through the gap in
the left side of the wall and this time follow the wall round to the right and
you will see an area where there is a low wall, this is the exit to the level.
Go through it and swim along the corridor, avoiding or killing the sharks.  When
you get to the end there will be a strong current that is stopping you exiting
the level.  Nearby is another Vigour Glyph (what a helpful Guardian, leaving
these things in just the right place for you), which you will need to collect in
order to defeat the current and swim through the light into Trial Without Error.
Gfs 4801