Subwar 2050 (1993)

The year is 2050. Ocean is the next frontier, and war inevitably reached there. As an independent mercenary working for a corporate conglomerate, the player has to pilot the latest fighter subs to protect the corporate interests, so they can get rewarded with cold hard cash. With 5 different theater of operations (of varying difficulty) and an interesting mix of aerial and submarine tactics, this game can be described as Strike Commander under the sea, without the narrative.