I always thought he was referring exclusively to the first Mario Bros. (Hence the 2.5D aspect, insteal of full-on 3D) But then, the series as a whole being an inspiration isn't too far-fetched. Do note that Super Mario 64 came out in 1996, and Klonoa DtP came out at the very end of 1997. And Klonoa 2 came out in 2001. Though, I'm not too sure about that specific level being inspired by that other specific level. If we had some kind of proof, like actual confirmation from Yoshizawa himself, then this is sort of an "inconclusive" theory at best.
...That's not to say it's not entirely plausible. Maybe that one section of the level, in that cave-like dragon's maw (only when typing that did I realize how weird that part of the level was. :-/)...it certainly has that sort of sliding level feel to it...
...when you think about it, a lot of things in Lunatea's Veil had some surreal aspects to it- the haunted mansion, Ishra's Ark (and Ishra's Ark Revisited), the Mansion of Memories (or whatever it was called...actually, a large part of Mira-Mira was surreal), the Drained Sea of Tears, literally everything about Hyuponia...all of that had to have been inspired by SOMETHING. But what? One might say dreams, but (and I can't believe I'm using this as a quote, I apologize immensely) as that Inception movie pointed out, all ideas are created from some kind of subconcious thought, or something...
...You know what? I'm over-analyzing this. Clearly, Yoshizawa had some inspiration from the Mario series, but to what extent, we may never know.
