I'd go with either "nasty" or "torturous," depending if you mean the one that's hated or the one doing the hating. But heck, I suppose it could it be both. 😅
Or just failure.
I dunno, it looks like they succeeded at making it. It's what it exactly is that's the problem
They must have been under the influence to concoct such a monstrosity.
Thank you, but no