Remember in Castlevania: SOTN there was an upside down castle?  Could there be an upside down version of the compound found in Shadow Complex?
 
Look at the title of the game in the "box art"  See how the M and W mirror each other?  Could this be a hint?

That would be pretty sweet. If I had to guess though I would say probably not. Although they have openly stated that Castlevania provided direct inspiration so who knows.

What would be the point? Spending all that extra time to make sure the level design works both upside down and rightside up, for nothing more than a simple easter egg reference? If they want to add more gameplay i'm sure they can find a way to do it that fits the game a little better. 
 
I guess it's possible though, stranger things have happened. But I really don't see it happening given all the gameplay we've seen so far, especially the turret gun parts and whatnot, unless those are completely remove for the mirrored complex then I guess maybe, but I still don't see it happening.

The upside down castle was just the layout mirrored, it had all new enemies and stuff, so if they went that route of course you wouldn't have the same turret locations etc. But no, I don't think they'll do it as it just doesn't seem fit the game's style, though I suppose it could be a bonus mode that doesn't try to integrate itself into the storyline and setting like it did in Symphony of the Night.

Yeah, I highly doubt it would happen, but they have talked about there being plenty of easter-eggs in there, so who knows what goodies are hidden away.

no

Yeah man. If you defeat your girlfriend in the optional boss fight(you gotta find the two card keys -- gold and silver -- and equip them in the room with the digital clock) to prove your strength, she'll give you night vision goggles. Equip them in the final boss battle against your friend, and you should be able to see the cyberninja that's controlling him. Attack the ninja, and the microchip in your friend's brain will stop working. After a brief cutscene, the cyberninja will then retreat to the upside down complex, and you'll get access to it.

I hope so. They wouldn't have to design it to account for being upside down because like SOTN you probably have enough mobility options that the locations of doors and platforms aren't a factor.

" The upside down castle was just the layout mirrored, it had all new enemies and stuff, so if they went that route of course you wouldn't have the same turret locations etc. But no, I don't think they'll do it as it just doesn't seem fit the game's style, though I suppose it could be a bonus mode that doesn't try to integrate itself into the storyline and setting like it did in Symphony of the Night. "

Well it also depends on what skills you get in the game. It worked in SOTN because you had the super jump and bat/fog transofmraitons so you could travel anywhere regardless of the layout. It could apply to this too if later on you get some grappling hook and maybe scaling abilities...

I saw a video with the character walking on the ceiling with those friction boots I think, so it's sort of like an upside down room....