It looks like something's gone a little wonky with the latest version of USI; it loads to about 66%, and then displays the following error message in a popup:
The page at html-classic.itch.io says:
Error: Couldn't load project data at path ".". Is the .pck file missing? If you've renamed the executable, the associated .pck file should also be renamed to match the executable's name (without the extension).
Clicking "OK" on the message then causes the game to display the following:
"null function or function signature mismatch"