Thank you very much for your review, your critique is much appreciated! (The translation looks fine to me, for the most part. Granted I'm no linguist myself.)
It is possible to get past the frogs without taking damage, however I could try slowing them down just a smidge. I also just realized that I may have made the graphic a bit too big in comparison to the collision box; making it difficult to tell which part of the frog will actually damage you.
I did draw some cracks in the wood that falls that I thought were conspicuous enough. But, I suppose if you're playing on a lower resolution it might be hard to see them, so I'll see to applying a color change for a future release.
Unfortunately, interface design is still something I'm learning. Still, thank you for bringing this to my attention.
Glad you liked the boss battles! Yeah, I didn't want the boss fights to feel too frustrating, but I did want them to feel tricky enough so that the player could feel accomplished after beating them. It's great to know those worked out!