Ancient Rome wouldn't be all that different from a modern superpower if they had mastered electricity or figured out how to make concrete, and they missed out on those innovations only for lack of development time.
Actually, the Romans invented concrete - they even built harbours and large domes out of it.
The Parthians (contemporaries of the Romans) may also have known about DC electricity, viz. the Baghdad battery, which might have been used to electroplate gold and silver:
Perhaps this technology was the origin of Alchemy if the knowledge became corrupted through secrecy and mysticism?
Human ingenuity 2, ancient aliens 0.