How to get through mysterious hideway???
First, you need a bike
Second… I DUNNO
Yeah i can use bike in first floor but what next??
I think you need teserract @Shrey
It depends on what you want to do.
With both bike and tesseract you can get the egg for δNoibat and continuing the δDitto quest. With the aboves AND all legendary dogs you can unlock the remainder of the tower.
Bike puzzles are quite annoying