Ecco the dolphin

Ecco the Dolphin is a game originally developed for the Mega Drive and published by Sega in 1992. The player character dolphin who travels through time to combat hostile extraterrestrials in Earth's oceans and on an alien spacecraft. Attacking enemies is accomplished by making Ecco ram into them at high speeds.

Original description:

You are Ecco, a powerful young dolphin. A mysterious storm has swept your family from the sea. The search to find them will take you through vast underwater realms of treachery, beauty and adventure. Use your sonar to discover hidden caverns and unlock the secrets of crystal glyphs. Charge packs of bloodthirsty sharks. Dive deep... but don't linger too long, because you're a mammal and need air to breathe. In your quest, you'll discover that more than your family's safety is at stake. The fate of the whole world rests on your wits and fins.

- Explore over 25 giant levels of solving puzzles and fighting denizens of the sea.
- 8 Megs of aquatic excitement with password save.
- Knife through the waters, flip above the waves, with motions created from real dolphins.

Instructions

Enter - start;    Arrows - move;    X - boost;
Z - shoot out a wave of sonar (hold down to displaying a map);
C - The more rapidly you hit the C button, the faster you'll go;
Esc = exit fullscreen;

You can change keyboard settings, save (F5) and load (F8) the game.
Put your mouse over the game and choose your settings, you can also play the game in fullscreen.