people say: oh shit, here comes Mariano, everybody down!

yes, there are levels of lucidity.
for me there are only 4.

Non-Lucid = you don't know you are dreaming
Pre-Lucid = in the dream you say " oh yeah, this is a dream" (you get a moment of clarity, not lucidity) but you don't become lucid
Semi-Lucid = you become half-aware that you are dreaming, you know you are dreaming, but you are still in Auto-Pilot(doing things unconsciously like in a non-lucid), so we say that you know you are dreaming in a subconscious level
Lucid = you know you are dreaming, you are aware of it, and you are not in auto-pilot

very simple, as you can see