The Water Horse: Legend of the Deep is based on the movie by the same which in turn is based on a children novel by Dick King-Smith. It’s a tale about a young boy, Angus MacMorrow, who on the shores of Loch Ness finds an egg which hatches into a water horse. The game starts shortly after that when Angus needs to get food to the newborn little creature. The story of the game is told between missions with clips from the movie.
The player gets to control both Angus and Crusoe (the water horse). As mentioned before the game starts with Angus having to collect food for Angus. Angus is controlled from a top down perspective and has to sneak around the farm without being spotted by his mother or any of the soldiers that are patrolling the area. Each level has to be completed within a set time limit. Angus can use different objects to help him progress. Stones can be thrown to distract guards, four-leap can be used to avoid guards and wood planks and boxes can be used to cross streams and climb fences.
The player also gets to control Crusoe during different stages of growth. Depending on which stage he is in the gameplay will also differ. In the baby stage he needs to eat to grow. The player controls Crusoe in a barrel full of water and needs to catch apples that are dropped into the barrel before they sink. There’s both good and rotten apples and it’s important to only eat the good ones. In the toddler stage Crusoe needs to learn how to swim in a bath tub. This is done with a quick time event where the player has to press the right keys at the right time as they appear on the screen. In the teenager stage Crusoe needs to swim around a pond to find fish that he can eat. The more fish he eats the faster he swims, while the reeds and lily pads in the pond makes him slow down. In the adult stage the player controls a full grown Crusoe in the loch. Here Crusoe has to navigate through the loch while avoiding the different dangers of the loch such as mines, Victoria gun shells and photographer boats. At the same time Crusoe must find food and surface now and then to catch his breath.
Throughout the levels of the game the player will come across mosaic pieces that can be collected. In total there is 100 pieces and they can used to unlock clips from the movie. In addition to the story mode the player can also play through individual levels at any time, as long as these are unlocked in the story mode.