ADVS98 (Adventure System 98) is an engine for making adventure games and visual novels for the NEC PC-9801, the Japanese computer where most of those games lived from the mid-eighties to the late nineties. You write the game on a modern computer — in the browser editor above or any text editor — and get a floppy image that boots on a real PC-98 or in an emulator. It looks and sounds like a game from back then, because it runs on the same machine those games did.

There are two parts that meet at one file. The tools — the editor (p98ed), the compiler (p98c) and the disk tools — run on Linux, Mac, Windows or just in a browser tab. They take your script, PNGs and music and pack them into DATA.PAK. The engine — GAME.EXE, 16-bit C and assembly — runs under MS-DOS or FreeDOS(98) on the PC-98 and plays it.

The PC-98 never does anything modern: text is wrapped, pictures are turned into 16-colour planar art and music is compiled before any of it reaches the disk, so the old machine only does what it is good at.