Great game! I love the pixel art style of the game, and the theming works very well with the art. The gameplay is very fun as well, as I love the grapple hook movement, and the world is well designed. The NPCs strewn throughout the world help flesh it out very nicely, and the map is implemented very well. The jumping felt a bit slippery to me with no air drag, but I know the pain of doing physics based grappling while having platformer movement, I've been trying for years to get this type of movement right, and I think you did a good job of it anyhow! The only other thing that I can think of is that I wish there was more.
Great work!!