Ed Annunziata, the game's head designer, stated that Pink Floyd served as a major inspiration to the game's music. The song "Echoes" may be the origin for the protagonist's, and one of the game's final levels, "Welcome To The Machine", may be a reference to the Pink Floyd song of the same name.
Contributed by CosmykTheDolfyn
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Most of the artwork in the prehistoric era looks very similar, if not identical, to scientific artwork by Zdeněk Burian.
Contributed by Falcon457
In Origin Beach, there are two glyphs that are behind the walls in the top left and right corners of the level. These were put in by the developers to answer the question "Why do dolphins live in the sea?"

The left one says:
We hear song in the ocean!
We hear our kind in the sea!
Never have we heard songs in the sea!

The one on the right says:
You sing our song under the waves
Who are you?
Could we sing in the sea?
Could we live in the sea?
Perhaps we will try!
Contributed by Falcon457
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Ecco the Dolphin creator Ed Annunziata stated that he made the game so hard because he was paranoid that kids would rent the game and beat it over the weekend.
Contributed by MidwayCJ