Silver Age Powers
I've been reading the House of Secrets issues starting with Eclipso's debut and have hit issue #64. Thus far, Eclipso does not display super-strength or "partial invulnerability" or any other such thing; he is only able to shoot beams of light channeled through his "black diamond", and has a genius-level intellect that is equal that of his host, Bruce Gordon (he can build robots, handily manipulate people, fly airplanes, etc). In the Bruce Gordon portion of this article, it lists that Eclipso has generic super-villain powers, which I've yet to see. I will finish reading these issues and correct for any contrariness.