diff --git a/unpackager.js b/unpackager.js
index 3587b90..6af50f3 100644
--- a/unpackager.js
+++ b/unpackager.js
@@ -335,8 +335,8 @@ var unpackage = (function() {
       return unpackageBinaryBlob(decodeDataURI(dataURI));
     }
 
-    // HTML files generated by HTMLifier have an inline JSON options object with inline base64
-    const htmlifierOptions = text.match(/<script>\nconst GENERATED = \d+\nconst initOptions = ({[\s\S]+})\ninit\(initOptions\)\n<\/script>/m);
+    // HTML files generated by some versions of HTMLifier store the project as fields in initOptions
+    let htmlifierOptions = text.match(/<script>\nconst GENERATED = \d+\nconst initOptions = ({[\s\S]+})\ninit\(initOptions\)\n<\/script>/m);
     if (htmlifierOptions) {
       const htmlifierAssets = JSON.parse(htmlifierOptions[1]).assets;
 
@@ -368,6 +368,28 @@ var unpackage = (function() {
       };
     }
 
+    // HTML files generated by older versions of HTMLifier with TYPE === "json" have PROJECT_JSON and ASSETS constants
+    // https://github.com/SheepTester/htmlifier/blob/b80b860f64bf7c4a908f3c9e74bac6285b7a1687/hacky-file-getter.js#L166
+    htmlifierOptions = text.match(/var TYPE = 'json',\nPROJECT_JSON = "([^"]*)",\nASSETS = ({[^}]*}),/m);
+    if (htmlifierOptions) {
+      const projectJSON = decodeDataURI(htmlifierOptions[1]);
+      const assetsJSON = JSON.parse(htmlifierOptions[2]);
+
+      const newZip = new JSZip();
+      newZip.file('project.json', projectJSON);
+      for (const name of Object.keys(assetsJSON)) {
+        newZip.file(name, decodeDataURI(assetsJSON[name]));
+      }
+
+      return {
+        type: 'sb3',
+        data: await newZip.generateAsync({
+          type: 'arraybuffer',
+          compression: 'DEFLATE'
+        })
+      };
+    }
+
     throw new Error('Input was not a zip and we could not find project.');
   };