Bhakti is something which has no fixed set of rules. in fact, this is true for all the forms of Yoga, but, still other forms do have some skeleton in them, based on which, rest of the idol will be erected. However that is not the case with Bhakti. This is the reason, why the devotees (bhakt) of all era had to face so rigorous tests, before they were accepted to be a bhakt. Kali is not so much a refined era, and in fact Kali Yuga is the yuga where the false will be given an emblem of purity.