Submarine Hunter is the name of a game my father wrote for the Atari 800 and had published in a copy of Computer & Video Games magazine back in the 80s (back when games magazines printed source code for you to type in! times have changed...)

I remade the game for him as a present - by typing in the Atari 800 BASIC listing, running it through Atari800Emulator and building my game code off that. It is downloadable as a .BIN file below; it plays on real GBA hardware or just as well through a decent GBA emulator, such as Visual Boy Advance (version 1.8 beta also available below, for posterity)

Submarine Hunter GBA, downloadable here.
Visual Boy Advance 1.8 beta 3, mirrored here.