I've also found that LLMs typically just partially implement a given task/story/spec/whatever. The reviewer stage will also notice a mismatch between the spec and the implementation.
I have an orchestrator bounce the flow back and forth between developing and reviewing until the review comes back clean, and only then do I bother to review its work. It saves so much time and frustration.
One difference between this story and the various success stories is that the latter all had comprehensive test suites as part of the source material that agents could use to gain feedback without human intervention. This doesn’t seem to exist in this case, which may simply be the deal breaker.