Super Depth

Super Depth, also known as Anti-Submarine Warfare 2, is a freeware shooter created by Japanese indie group Bio_100%. Originally released for PC-98 in 1991, it later received a Flash web browser port and serves as the sequel to WinDepth. Players control a destroyer and fight across four stages: underwater seabed, sky, outer space and final boss battle, mixing vertical and horizontal shoot ’em up gameplay. Drop depth charges to sink submarines, fire bullets to destroy helicopters and battle massive space bosses. Enemies include regular submarines, red subs with homing torpedoes, missile launchers and giant serpent bosses. Explosions from nearby enemies can damage your own ship. It uses keyboard controls and retro pixel art with chiptune soundtrack. The original release is Japanese freeware. The Flash port can be played via Ruffle Flash emulator, a beloved classic Japanese doujin shooter and retro Flash submarine shooting game.

These games get the keyboard directly — the controls are whatever the game itself defines, usually in its own help or options screen. Some games show on-screen buttons on phones.