To use the tool, select a ZX Spectrum snapshot file (in .sna or .z80 format), Atari snapshot file (in .xex format) or C64 snapshot (in .vsf format) from your local filesystem. If this snapshot contains a valid Quill adventure then the tool will allow you to play it in your web browser. Not all games work, particularly later-era games that include compressed text. Graphics and UDGs are not supported yet.
You may ask what the point of this tool is when you can already play the games in an emulator. In addition to some UI features (inventory, direction buttons and command history), I've implemented a host of additional 'debug' type commands that you can use to examine or alter the state of the game whilst playing it. Type '*HELP' whilst playing a game to find out more.