SSN-21 Seawolf is a submarine simulator game designed by John W. Ratcliff and published for MS-DOS systems by Electronic Arts in 1994.The player takes command of a US Seawolf-class submarine and fights in 33 missions with targets under and above water including fast Russian attack subs, destroyers and rocket frigates.The game is a sequel to Electronic Arts' 688 Attack Sub, and has a similar mission structure and variety.