What a well-designed, welcoming and pristine Hostel! Two suggestions:
1) a "lights out"/Quiet time suggestion or enforcement of some sort. The "rooms" are curtained off cubbies, perfectly fine, but our neighbor across from us kept his light on and was noisy throughout the night and so we didn't sleep well, despite the beds' comfort.
2) uniform temperature for the facility was kept very warm, making top bunk area particularly hot. Suggest small, quiet fans for each bunk to help regulate temps to individual preference levels.