Download keys are per-project, not per-file, and give access to everything, just like when people buy the game. So no. :)
That's a relief, good to know that!
I have few other related questions, if I update my game, how will the interface looks like for those who have purchased the game?
Will it simply shows "update" (or similar)?
Last, if I upload Mac and Linux version, does the people who purchase Windows version have access or will they have to buy another version separately?