I'd like to point out that the indicated version of "SQL Code Guard" is no longer available. The product was bought up by Red Gate and added to their existing product list with some new packaging. Their version is ONLY compatible with SSMS 2016, and provides no backwards compatibility.
Oleksii's old site now redirects to the relevant Red Gate page, meaning it's unlikely the older installations compatible with prior SSMS versions would no longer be available.
If anyone finds a link for the older versions, or finds another SSMS add-in that provides similar functionality for free, please post it here for reference.