Savvy DOCX Recovery is a free tool which attempts to repair damaged Microsoft Word documents (DOCX).
After installing and launching the program, it worked much like similar tools. There's nothing much to figure out, just click "Browse", select your broken file and click Recover to try and repair it.
Performance seemed disappointing, at least initially. Savvy DOCX Recovery said it couldn't recover our test file, offered to try and extract just the document text, and failed there too.
But then we closed the program, and noticed it had left a [name].docx.savvy_fix.docx file in the same folder as our source document. This wouldn't open in Word, but if we extracted its contents (rename the file to .zip if you have any problems) then this produced a lot of useful data. Opening Word\Document.xml gave us the text-only (no formatting) content of our document, for instance, and with some manual tweaking it might have been possible to recover more.
Savvy DOCX Recovery didn't deliver for us, failing to repair test documents which the commercial competition fixed without difficulty.
BUT... With a little extra manual work, we did manage to recover the raw text from one file. You might be luckier with your documents. And there's no eye-watering price tag, a major plus in this area.
On balance, we say try it, but don't expect too much. (Or anything at all, really.)