Styx

This is a homebrew  game, run on Gameboy Color. Original version:  Matthew Smith - Bug-Byte - ZX-Spectrum, 1983. Created with GB-Studio 2.0.0 beta5! 

Also available for download in .CIA format for the Nintendo 3DS virtual console!

Armed with your laser gun, you must battle your way across the river Styx toward Hades. The game is in three phases. In the first phase you must make your way through the spider-filled maze and dive into the river Styx. In the river stage you come up against deadly pirahnas which seem non too keen on letting you cross to the other side. having dragged yourself out on the far beach, you find yourself fighting your way through the Infernal Regions, past the Spirits of the Dead, towards an encounter with the Dark One himself.

 

Start the game: A
Move: Cursor keys  
Fire: A 

Start the game: Z
Move: Arrow keys
Fire: Z

 https://spectrumcomputing.co.uk/entry/0004974

You can download the ROM file of the game from the WLS website!