30 regular maps + 2 secret maps, more than 8 regular + 1 secret (per episode) in the original Doom. Remember, Ultimate Doom (with the forth episode) came out after Doom II.
And even though Quake had an episodic format, it wasn't of a consistent length (eps 1 and 4 were 8 levels each, 2 and 3 were 7, plus the intro and end levels = 32)