Marlowe and Shakespeare were the same age. Marlowe died at 29 having already established himself as playwright, poet and man about town whereas Shakespeare was a late developer, and only appeared as an author- with the Marlovian Venus and Adonis- a couple of months after Marlowe's death. The one takes up where the other finishes.
I read Marlowe's Edward II. It's has all the qualities we call Shakespearian- the poetry, the stagecraft, the ability to see all sides of a question, the mastery of pathos- and resembles Richard II to the point of making the later play seem like an imitation or riposte- but one that improves on the original- which is not something one expects a mere copyist to pull off- unless of course- it were a case of a master in competition with himself.
So either we have two great writers- of an age- with remarkably similar skill-sets- the one beginning his career just as the other cashes in his chips- or else...