I ended the threat, the boss fight was super cool and fit perfectly.
The game is very fun. I'm not even fan or going back from the start plenty of times but the game looks, sounds and feels great. It controls perfectly with the right speeds (default speed + dash is perfect) and feedbacks, one thing I specially like is that your slash more or less goes above your head, I always feel like I'm doing some weird thing when it doesn't. All the abilities are satisfying to find and cool to use, in practice I almost didn't use grappling but bomb jump + grappling felt great anyway, and the bomb jump is super cool. I like the different upgrades including damage/2 & damagex2 and the difficulty of the game is perfect, I died a couple of times. The enemies are different and they propose the right amount of fair threat and I like the sparse water from floor 13 including the sequence with water, one pink enemy and the double headed one, I died at least once there after completing a mission and trying to go back, that's pretty cool. Once again the boss fight is super cool too and just hard enough that you should not need more than a couple of tries but it's satisfying to beat it anyway. Finally the game totally feels like a NES game maybe just a bit smoother on various fronts which is not a bad thing.