Submarines (lost build of cancelled arcade game sequel; 1999)
At the Amusement Machine Operator's Union (AMOU) tradeshow in 1999, Namco demonstrated an arcade game titled Submarines. It was intended as a sequel to Submarine, an older Namco electro-mechanical game from 1978. The game followed the same basic gameplay structure as the original, where players were to destroy waves of enemy submarines by firing torpedoes. Submarine featured a unique periscope-type interface that players would move to look around in the in-game world. The plot involved the player trying to stop a terrorist organization from launching stolen nuclear weapons attached to submarines.
Submarines was featured in a broadcast aired by Hong Kong TV that covered the expo, which shows what the gameplay looked like. Much of the information behind the game, including why it was cancelled and if a prototype still exists, is unknown. As such, the game's promotional flyer and light coverage from Japanese gaming publications are the only pieces of evidence that prove the game's existence.