UIM is a 3D arcade adventure, an underwater version of Elite, set in a future where all life exists in the oceans. You travel the oceans in a submarine, trading in commodities, shares and currency, and seeking the UIM. You will need to purchase system and weapon upgrades to combat hostile forces. There are over 65000 underwater ports with their own colonies to visit and over 250 missions to complete before you finally encounter the UIM.